Pocket Genius

Elements

FACTS AT YOUR FINGERTIPS

 DK DELHI
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CONTENTS
4 What is an element? 68 LANTHANIDES 110 NITROGEN GROUP
8 Inside an atom
72 Lanthanum, Cerium, 114 Nitrogen
12 Grouping the elements Praseodymium 116 Phosphorus, Arsenic
14 Periodic table 74 Neodymium, Promethium, 118 Antimony, Bismuth,
Europium, Samarium, Moscovium
Gadolinium
16 HYDROGEN 76 Terbium, Dysprosium, 120 OXYGEN GROUP
Holmium
18 Hydrogen 124 Oxygen, Sulfur
78 Thulium, Erbium,
Lutetium, Ytterbium 128 Selenium, Tellurium,
20 ALKALI METALS Polonium, Livermorium
24 Lithium, Sodium, 80 ACTINIDES
Potassium 130 HALOGEN GROUP
84 Actinium, Thorium,
28 Rubidium, Cesium, Protactinium 134 Fluorine, Chlorine,
Francium Bromine
86 Uranium, Neptunium,
Plutonium 136 Iodine, Tennessine,
30 ALKALINE EARTH Astatine
METALS 88 Americium, Berkelium,
Einsteinium, Curium,
138 NOBLE GASES
34 Beryllium, Magnesium, Californium
Calcium 90 Fermium, Mendelevium, 142 Helium, Neon, Argon
36 Strontium, Barium, Radium Nobelium, Lawrencium 144 Krypton, Xenon, Radon,
Oganesson
38 TRANSITION METALS 92 BORON GROUP

42 Scandium, Titanium 96 Boron, Aluminum

146 Fascinating facts
44 Vanadium, Chromium, 98 Gallium, Indium, Thallium,
Nihonium 148 What’s in a name?
Manganese
150 Glossary
46 Iron, Cobalt 100 CARBON GROUP 152 Index
50 Nickel, Copper, Zinc
104 Carbon, Silicon 156 Acknowledgments
52 Yttrium, Zirconium,
Niobium, Molybdenum 108 Germanium, Flerovium,
Tin, Lead
54 Technetium, Ruthenium,
Palladium, Rhodium
ATOMIC MASS: The relative atomic mass of an element. This is the
56 Silver, Cadmium, Hafnium average of the atomic masses of all the forms of an element. In cases
58 Tantalum, Tungsten, where the relative atomic mass is not known, the atomic mass of an
Rhenium, Iridium, Osmium element’s most stable form is given within brackets.
60 Platinum, Gold STATE: The state of an element at 68°F (20°C).
64 Mercury, Rutherfordium, DISCOVERY: The year in which an element was discovered,
Dubnium, Seaborgium along with the names of the discoverers. When different people
66 Bohrium, Hassium, have discovered an element separately, individual dates are given
Meitnerium, Darmstadtium, for each discoverer.
Roentgenium, Copernicium
4 | ELEMENTS

What is an element?
An element is a substance that cannot be refined or purified
into simpler ingredients. Elements are made of building
blocks called atoms and each element has its own unique
set of atoms. Everything in the universe is made from
elements, either in their pure form, or combined together
to make new substances called compounds.

Classical elements
The idea of an element is very old. In
ancient cultures, people believed that all
things were made from mixtures of just
four elements: earth, water, air, and fire.
They thought that hot and dry things
Earth Water
contained fire and air, while cold and
wet things were made of earth and water.

Air Fire

Modern elements
The scientific study of the properties and
reactions of elements is called chemistry. This
has found that there are at least 118 elements.
Most elements are created inside a star or in
a supernova—the explosive ending of a big
star’s life. Scientists have also been able to
create the heaviest elements in laboratories.

The Crab Nebula, the remains of

a supernova, is rich in hydrogen.
 WHAT IS AN ELEMENT? | 5

Types of element
Atoms are made of smaller “subatomic” particles called
protons, electrons, and neutrons. The properties of an element
depend on how these particles are arranged. Elements with
the same number of electrons in the outermost shell of their
atom have similar physical and chemical properties. Metals
mostly have one or two outer electrons, semi-metals have
three or four, and nonmetals have up to eight.

Powdery form
of phosphorus
(nonmetal)

Crystals of Chunk of boron

gold (metal) (semi-metal)

Building blocks Others 0.1% Phosphorus 1% Others 1%

Everything in the universe is Argon 0.9%
Nitrogen 3% Calcium 1.5%
made up of the many types
of elements arranged in different Oxygen 21% Hydrogen 10%
combinations. That includes
living things such as humans. Carbon 18.5%
The human body is made of Nitrogen 78%
60 different elements. Just six Oxygen 65%
of them make up 99 percent of
the body’s weight, while the
other 54 make up the remaining
1 percent. Amazingly,
only three elements make up
most of Earth’s atmosphere.
Earth’s atmosphere Human body
6 | ELEMENTS

States of matter
Every element has a standard state—solid, liquid, or gas—
at room temperature. The atoms of a solid fit together in
a tight-knit pattern, while in a liquid the atoms are loosely
connected so they flow around. In a gas, the atoms are
free of each other and disperse easily. Applying heat can
change the state of an element from solid to liquid, and
then to gas, or even from solid to gas in some cases.

Chlorine gas in
a glass sphere

Liquid mercury
in a vial

Solid crystals of bismuth

refined in a laboratory

Pure forms Gold in

A pure sample of an element contains quartz
only atoms of that element. Only a
few elements are found pure in nature
in significant amounts. These include
gold and sulfur (in the ground), and
oxygen (in the air). Many elements
This vein of pure
are found in ores. gold has occurred
naturally inside a
chunk of quartz.
 WHAT IS AN ELEMENT? | 7

Ores
A naturally occurring substance—rock,
sand, or crystal—that contains a large
amount of an element is called an ore.
Ores are mined so that the elements
they contain can be removed. Some
ores contain more than one element.
The mineral malachite (right) is an ore of
copper, and chemical reactions are used
to extract the metal from the ore.

Malachite

Copper flakes reacting Mixtures

with nitric acid to form Elements combine chemically to form
two compounds compounds, and it takes a chemical
reaction to break the bonds
The red-brown gas
is nitrogen dioxide, a between the atoms in a
compound of nitrogen compound to separate the
and oxygen. elements. On the other
Copper nitrate,
hand, a mixture is formed
a green, solid when compounds or
compound, in elements are combined
nitric acid
physically. An alloy is a
mixture of at least two
Compounds elements, one or all of
Most elements do not stay pure in nature which are metals. In a
for long. Instead they react with other mixture, elements may
elements they come into contact with, be so thoroughly mixed
which results in the atoms of two or more that they are impossible
elements bonding together to make an to tell apart.
entirely new substance called a compound.
Mixture of food
The properties of a compound are always coloring and water
very different to the elements that make it.
8 | ELEMENTS

Inside an atom
An atom is the smallest unit of an element.
Every element has atoms made of a unique
combination of even smaller particles, known
as subatomic particles. These are the
electrons, protons, and neutrons.

Subatomic particles
In an atom, protons and neutrons are located in its core,
or nucleus. Changes to these particles are called nuclear
reactions. The electrons, located outside of the nucleus,
participate in chemical reactions, helping elements
combine to form compounds.

Atomic number
An element’s atomic number is defined by the number of
protons in one of it’s atoms. Every element has a unique
atomic number. Hydrogen has the lowest atomic number
(1) among the elements as it has only one proton. The
number of electrons in an element always matches
the atomic number.

8 electrons
in 2 shells
3 protons
1 proton
4 neutrons

8 protons

1 electron 8 neutrons
in 1 shell 3 electrons
in 2 shells
Hydrogen atom Lithium atom Oxygen atom
(atomic number 1) (atomic number 3) (atomic number 8)
 INSIDE AN ATOM | 9

Protons: These particles have a

positive electrical charge. This charge
attracts the negatively charged
electrons, holding them in place around
the nucleus. The positive and negative
charges cancel out each other, so an
atom has a neutral charge.

Electrons: Negatively
charged electrons were
the first type of subatomic
particle to be discovered.
They are almost 2,000 times
smaller than protons.

Nucleus: Almost all of an

atom’s weight is packed
inside the nucleus. Even
so, it is 100,000 times
smaller than the atom
as a whole. Most of an
atom is empty space.

Neutrons: A neutron has

no overall electrical charge,
and helps protons cluster
together in the nucleus. It
adds weight to the atom.

Electron shell: Electrons are arranged in

layers, or shells, around the outside of an atom.
Each atom of an element has a unique number
of electrons, arranged in a particular way in its
electron shells. The shell closest to the nucleus
has room for just two electrons, but shells
located further out have room for more. Only
the electrons in the outermost shell participate
in chemical reactions.
Structure of an atom
10 | ELEMENTS

Atomic mass
The atomic mass of an element is measured
as the total number of protons and neutrons
An oxygen 16 hydrogen
atom atoms in each of its atoms. Hydrogen has an
atomic mass of 1, while oxygen’s is
16—one oxygen atom weighs as much
as 16 hydrogen atoms. Since an
element can have different isotopes
(forms), scientists use its relative
atomic mass. This is the average
of the atomic masses of all the
isotopes of an element.

Isotopes
While an atom of an element has a unique number of protons and electrons,
the number of neutrons in it may vary. This creates different forms of the same
element, known as isotopes. For example, hydrogen has three isotopes.

Neutron

Hydrogen has Deuterium (an isotope of Tritium (an isotope of

no neutrons. hydrogen) has 1 neutron. hydrogen) has 2 neutrons.

Forming molecules
During chemical reactions, atoms make bonds
Oxygen
atom with each other to form structures called molecules.
Molecules of elements contain atoms of the same
element, while molecules of compounds are made
of atoms of different elements. For example, a water
molecule forms when an oxygen atom bonds to two
Hydrogen Hydrogen hydrogen atoms. This molecule is the smallest
atom atom possible unit of the compound called water.
 INSIDE AN ATOM | 11

Allotropes
Several elements have multiple physical
forms, or allotropes. For example,
carbon has four allotropes: diamond,
graphite, soot (or charcoal), and
buckminsterfullerene. They are all
Piece Diamond made from pure carbon, but look
of charcoal crystal and feel very different.

Radioactivity
While the main isotopes of most elements are
stable, some rarer isotopes are less stable and As another nucleus is hit,
the nuclei of their atoms break apart on their own. a chain of nuclear fission
reactions starts.
This process is called radioactivity, which releases
dangerous particles and a lot of energy. These
include positively charged alpha particles,
Released
negatively charged beta particles, and gamma neutron
rays, which carry no charge. Large, or heavy, hits another
unstable
atoms are less stable, and all elements with an uranium atom.
atomic number above 82 are radioactive.
Nuclear power stations use radioactivity
from nuclear fission, a process in which
atoms are split in two. Neutrons, as well as
heat and other energy,
are released when the
uranium atom splits.
When the neutron collides with the uranium
atom, the atom splits into two parts.

Neutron fired at
uranium atom

Nucleus of unstable
uranium atom
Nuclear fission reaction
12 | ELEMENTS

Grouping the elements

Chemistry is the science that seeks to understand how elements
behave and how they combine into compounds. In order to
achieve this, chemists began trying to organize all known
elements according to their physical and chemical properties.
Over 200 years later, the result is the modern periodic table,
which arranges elements by the similarity of their properties.

Antoine Lavoisier
In 1789, the French scientist Antoine Lavoisier produced an early
list of chemical elements, which he called “simple substances.”
Lavoisier’s list had 55 entries, divided into metals, nonmetals,
and gaseous elements, such as oxygen.

Drops of the
liquid metal Pure oxygen gas in Yellow crystals of the
mercury a glass sphere nonmetal sulfur in rock

Johann Döbereiner Shiny solid

The German chemist Johann Döbereiner showed
in 1817 that most elements could be grouped
into threes (or “triads”). Some elements were
“missing” at the time as they had not yet been
discovered, and this finding encouraged the
search for new elements in the 19th century. Potassium kept inside
an airless glass vial
Elements in each triad—such as lithium, sodium,
and potassium—shared chemical properties.
 GROUPING THE ELEMENTS | 13

Henry Moseley
Mendeleev’s table worked very well,
but no one really knew why. In 1913,
the British physicist Henry Moseley
discovered the concept of the atomic
number—the number of protons
in an atom of an element, which is
unique to that element. He used X-rays
to calculate the atomic numbers of
elements, which could now be
organized on the basis of
their atomic number
instead of their
atomic mass.

Henry Moseley

Dmitri Mendeleev’s handwritten

periodic table from February 1869

Dmitri Mendeleev
In 1869, the Russian chemist Dmitri
Mendeleev invented the forerunner of
the modern periodic table. He saw that
elements had chemical properties
that followed a repeating pattern and
those with similar patterns could
be grouped together. He listed
the elements in order of atomic
mass, starting a new section
with every new pattern.
14 | ELEMENTS

Periodic table
Period
numbers
The periodic table organizes the 118 known
1 Group elements by arranging them based on their
numbers
1 atomic number, which is the number of protons
1 H in each of their atoms. The elements are placed
Hydrogen
2 in rows (called “periods”) and columns (called
3 4 “groups”). Elements with similar properties sit
2 Li Be in a group. This table is “periodic” because the
Lithium Beryllium
characteristics of the elements follow a pattern.
11 12
New elements may be added to it in the future.
3 Na Mg
Sodium Magnesium
3 4 5 6 7 8 9
19 20 21 22 23 24 25 26 27
4 K Ca Sc Ti V Cr Mn Fe Co
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt

37 38 39 40 41 42 43 44 45
5 Rb Sr Y Zr Nb Mo Tc Ru Rh
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium

55 56 57–71 72 73 74 75 76 77
6 Cs Ba Lanthanide Hf Ta W Re Os Ir
Cesium Barium series Hafnium Tantalum Tungsten Rhenium Osmium Iridium

87 88 89 –103 104 105 106 107 108 109

7 Fr Ra Actinide Rf Db Sg Bh Hs Mt
Francium Radium series Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium

These two rows, known 57 58 59 60 61 62

as the Lanthanides La Ce Pr Nd Pm Sm
and Actinides, are not Lanthanum Cerium Praseodymium Neodymium Promethium Samarium
periods. They sit next to
Group 2, but make the 89 90 91 92 93 94
table very wide, so are
moved to the bottom.
Ac Th Pa U Np Pu
Actinium Thorium Protactinium Uranium Neptunium Plutonium
 PERIODIC TABLE | 15

KEY
Hydrogen Lanthanides Nitrogen Group
Alkali Metals Actinides Oxygen Group
Alkaline Earth Metals Boron Group Halogen Group
Transition Metals Carbon Group Noble Gases
18
The atomic number is Group: A column of elements with the 2
unique to each element. same number of electrons in the outermost
shell of each of their atoms.
He
Helium
29 Each element 13 14 15 16 17
has a unique
Cu symbol made
5 6 7 8 9 10

Copper of letters.
B C N O F Ne
Boron Carbon Nitrogen Oxygen Fluorine Neon
Period: A row of elements 13 14 15 16 17 18
with the same total number of
electron shells in their atoms. Al Si P S Cl Ar
Aluminum Silicon Phosphorus Sulfur Chlorine Argon
10 11 12
28 29 30 31 32 33 34 35 36
Ni Cu Zn Ga Ge As Se Br Kr
Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton

46 47 48 49 50 51 52 53 54
Pd Ag Cd In Sn Sb Te I Xe
Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon

78 79 80 81 82 83 84 85 86
Pt Au Hg Tl Pb Bi Po At Rn
Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon

110 111 112 113 114 115 116 117 118

Ds Rg Cn Nh Fl Mc Lv Ts Og
Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson

63 64 65 66 67 68 69 70 71
Eu Gd Tb Dy Ho Er Tm Yb Lu
Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium

95 96 97 98 99 100 101 102 103

Am Cm Bk Cf Es Fm Md No Lr
Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium
 1
He
H

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

La-
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Lu

Ac-
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Lr

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Hydrogen
The simplest of all elements, hydrogen has
only one proton and one electron. It is the
most abundant element in the universe—
the sun, like all other stars, is a vast ball
of seething hot hydrogen gas.
18 | ELEMENTS

Hydrogen
Three-quarters of all the atoms in the universe are
FOCUS ON… hydrogen—the lightest of all the elements. The heat and
HYDROGEN light from stars, including our sun, comes from hydrogen
atoms fusing into helium atoms in each star’s core. In fact,
This gas is found in very
useful chemicals and even in all heavier elements started out as these small atoms,
the human body—one tenth which have gradually fused together.
of which is made of hydrogen.
Stars form inside a nebula,
which is a cloud of hydrogen
gas and some dust.

▲ Hydrogen is used in the

production of margarine
to thicken it.

▲ A new generation
of environment-friendly
cars use fuel cells
powered by hydrogen.

◀ Liquid
hydrogen is
used as rocket
fuel. Combined
with oxygen, it
produces the
thrust to power
a rocket.
 HYDROGEN | 19

1
H
ATOMIC MASS 1.008
STATE Gas
DISCOVERY 1766 (Henry Cavendish)

Hydrogen gives
off a purple glow
when electrified.

Pure hydrogen gas

in a glass sphere

The Carina Nebula is

home to clusters of
old and new stars.
H He

3
Be B C N O F Ne
Li
11
Mg Al Si P S Cl Ar
Na
19
Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
K
37
Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Rb
55 La-
Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Cs Lu
87 Ac-
Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Fr Lr

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Alkali Metals
All alkali metals are highly reactive, so they
form compounds easily and are found in many
minerals. The walls of this potash mine have
orange and white stripes due to the many
potassium compounds being mined.
22 | ELEMENTS

Alkali Metals
As well as hydrogen, the first column of the periodic table contains the
alkali metals, a group of six elements that react vigorously with water
to produce chemicals known as alkalis. Members of this group are
soft enough to cut with a knife. They are never found pure in nature,
but always as a compound, from which the pure metal is extracted.

Blue-violet flame of Easily tarnished

burning cesium Freshly cut or scraped alkali metals are
shiny, but turn dull as their surface reacts
Colored flames with oxygen in the air and forms a thin
Each alkali metal burns with layer of the metal’s oxide. In laboratories,
a distinctive color. While lithium the metals are stored in oil to prevent this.
burns with deep-red flames,
potassium’s flames are lilac, and
sodium’s are yellow. Chemists
look for these colors to identify
the metals involved in reactions.

Piece of
burning cesium Oxide layer gives this piece of
lithium a dull appearance.

Highly reactive
Alkali metals are usually stored in oil because they are
so reactive to the oxygen and water vapor in the air
that some of them will burst into flames when they
come into contact with it. Lithium tarnishes in the
air, but doesn’t ignite until it is heated (as pictured
on the left). It combines with oxygen to form a
whitish compound called lithium oxide.
 ALKALI METALS | 23

Salt compounds
Alkali metals react with halogen elements to create salts,
such as sodium chloride. These are white crystals that
dissolve in water very easily. An example of this is sea Salt evaporation pools
at Salinas de Janubio,
salt, which is mostly sodium chloride, but also contains Lanzarote, Canary Islands
potassium chloride and trace amounts of other salts.

Pile of salt
crystals remaining
after evaporation
of sea water
24 | ELEMENTS

3
Lithium Li
The main natural source of lithium ATOMIC MASS 6.94
is the thick layer of salt left over from STATE Solid
when ancient lakes and seas dried
out. This alkali metal is used to make DISCOVERY 1817 (Johan
long-lasting batteries inside cell August Arfvedson)
phones and electric cars.

Purple crystals in
this rock contain Lithium is the lightest
lepidolite, an of all metals; it will
ore of lithium float on water even
as it reacts with it.
 ALKALI METALS | 25

FOCUS ON…
SODIUM
The use of sodium
dates back thousands ▲ Ancient Egyptians used a ▲ Sodium chloride, ▲ Sodium compounds
of years. sodium compound, natron, or common salt, adds give some fireworks
to preserve mummies. flavor to foods. their yellow color.

11 19
Sodium Na Potassium K
The most common alkali metal in Earth’s This metal helps the nerves and muscles in
crust, sodium is purified by electrifying the body work properly. Potassium is found
through sodium chloride. The electric in foods such as bananas and avocados.
current splits the sodium and chlorine Its compounds are used in soaps, plant
apart in a process known as electrolysis. fertilizers, and gunpowder.

ATOMIC MASS 22.99 ATOMIC MASS 39.098

STATE Solid STATE Solid
DISCOVERY 1807 (Sir Humphry Davy) DISCOVERY 1807 (Sir Humphry Davy)

Nugget of A layer of
pure sodium dark oxide
covers the
outside of
the metal.

Pure
potassium

Nugget of
potassium
LAKE NATRON
Tanzania’s Lake Natron is filled with a natural supply of
sodium salts, such as sodium carbonate, which wash
out of the volcanic rocks in the region. The water is
more alkaline than baking soda—perfect for the rapid
growth of a kind of bacteria that turns the lake red.
 Any creature that falls into
Lake Natron quickly gets covered in
sodium salts and looks as if it has been

turned to stone
28 | ELEMENTS

37 87
Rubidium Rb Francium Fr
This metal is very rare compared to other The atoms of this radioactive element exist
alkali metals. Rubidium is named after only for a few minutes before breaking
the Latin word for “red” as it produces a up. As a result, francium is one of the
deep-red flame when it burns. It is used rarest elements. This metal was one of
only in a few high-tech applications, such the last elements discovered in nature
as night-vision goggles. because of its rarity. It was named after the
country in which it was first found, France.
ATOMIC MASS 85.468
STATE Solid ATOMIC MASS (223)
DISCOVERY STATE Solid
1861 (Gustav DISCOVERY 1939 (Marguerite Perey)
Kirchhoff and
Robert Bunsen)
As the uranium in this ore breaks
down, it releases actinium
Leucite, an ore atoms, which in turn break down
of rubidium to release francium atoms.

55
Cesium Cs
The most reactive metal found
on Earth, cesium explodes
violently on contact with
air. It is used in atomic
clocks, the most accurate
timepieces yet invented.

ATOMIC MASS
132.905
STATE Solid
DISCOVERY 1860
(Gustav Kirchhoff and
Robert Bunsen)
Chunk of uraninite,
Laboratory sample of an ore of francium
pure cesium in an
airless vial
 ALKALI METALS | 29

The largest sample

of francium ever
collected was 1 million
atoms, in a US
laboratory in 2012.
 H He

4
Li B C N O F Ne
Be
12
Na Al Si P S Cl Ar
Mg
20
K Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ca
38
Rb Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Sr
56 La-
Cs Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Ba Lu
88 Ac-
Fr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Ra Lr

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Alkaline
Earth Metals
The elements in this group appear in nature as
minerals, or “earths,” that mix easily with water
to form compounds called alkalis. The minerals
of calcium are the most common because they
are found in living things—even in the shell of
this fossilized ammonite.
32 | ELEMENTS

Alkaline Earth Metals

Forming the second column—or Group 2—of the periodic table,
these metals are not quite as reactive as their neighbors, the
alkali metals, which form Group 1. Most alkaline earth metals were
first found in Earth’s crust as oxide compounds. Solid at room
temperature, these elements have low melting and boiling points.

Magnesium
can be made
into a flexible ribbon

Soft metals Silvery shine

Most members of this group are soft, brittle Pure alkaline earth metals, such as
metals when pure, and are easy to cut with calcium (seen above), are shiny.
a knife. They also break easily when they These metals are highly reflective
are dropped or twisted. One exception is and have a very smooth surface,
beryllium, which is a hard, tough metal. which creates a mirrorlike shine.

Making alkalis
The crumbly minerals of these elements dissolve in
water to form chemicals called alkalis. In the past,
these minerals were called “earths,” which inspired
the name of the group.

Magnesite, a mineral
of magnesium
 ALKALINE EARTH METALS | 33

Colorful flames
When alkaline earth metals react
with oxygen in the air, they burn
and release energy in the form
of light and heat. Each member of
this group burns with a distinctive,
colored flame. Magnesium
produces a particularly bright
white flame (pictured right).

Magnesium powder
produces the bright
white sparkles
of fireworks.

Fireworks display
at Sydney Harbor
Bridge, Australia
34 | ELEMENTS

4
Beryllium Be
While other metals expand when
hot and contract when cold,
beryllium keeps its shape at all
temperatures. This means it can
be used in machines such as
high-speed aircraft, in which
some parts may become
extremely hot.

ATOMIC MASS 9.012

STATE Solid
DISCOVERY 1797
(Nicholas Louis Vauquelin)

Laboratory sample of
pure beryllium

12
Magnesium Mg
Pure magnesium is added to other metals such
as iron, not only to make them stronger but also
more lightweight. Useful compounds
of magnesium include magnesium
carbonate, which is used in
medicine for indigestion, and
magnesium oxide, which is
found in cement.

ATOMIC MASS 24.305

STATE Solid
DISCOVERY 1755
(Joseph Black)

Laboratory sample of
pure magnesium
 ALKALINE EARTH METALS | 35

FOCUS ON…
CALCIUM
This element is the most
common alkaline earth ▲ Writing chalk is ▲ Milk is a source ▲ The Sphinx of Giza
metal in Earth’s rocks, mainly made of a of calcium and helps is made from limestone,
and the most abundant calcium sulfate mineral to strengthen our a rock formed primarily
metal in the human body. known as gypsum. bones and teeth. of calcium carbonate.

20
Calcium Ca
The pure form of calcium reacts with water to make
hydrogen gas and calcium hydroxide, a compound used in
paper-making. The fifth most common element in Earth’s
crust, calcium is found in many minerals, very often as
calcium carbonate. This compound appears in many
forms, including calcite crystals.

ATOMIC MASS 40.078

STATE Solid
DISCOVERY 1808 (Sir Humphry Davy)

Clear crystals of
calcite, an ore
of calcium

Crystals of pure calcium

refined in a laboratory
36 | ELEMENTS

Strontium
This metal is named after Strontian, a
village in Scotland near where the first
samples of strontium minerals were
discovered. Strontium has a wide range
of uses, including in fireworks that burn
red and toothpastes for people with
sensitive teeth.

ATOMIC MASS 87.62

STATE Solid
DISCOVERY 1787 (Adair Crawford),
1791 (Thomas Charles Hope)
The grayish
metal turns
yellow in the air.

Blue crystals of celestine,

an ore of strontium
 ALKALINE EARTH METALS | 37

38 56
Sr Barium Ba
The name of this element comes from the
Laboratory-refined Greek word for “heavy.” Barium is not
crystals of pure strontium radioactive or poisonous (unlike
most other heavy metals) so can
be swallowed during medical
tests to make the digestive
system clearer in X-rays.
A radioactive form
of strontium is used to ATOMIC MASS
generate electricity in 137.327
some remote areas, STATE Solid
such as towns DISCOVERY 1808
in the Arctic. (Sir Humphry Davy)

Blue crystals of
benitoite, an ore
of barium, in rock

88
Radium Ra
Tiny amounts of radium can be found
in ores of more common radioactive
elements such as uranium. Radium was
one of the first radioactive
elements ever discovered.

ATOMIC MASS (226)

STATE Solid
DISCOVERY
1898 (Marie and
Pierre Curie)

Chunk of
uraninite, an
ore of radium
 H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

21 22 23 24 25 26 27 28 29 30
K Ca Ga Ge As Se Br Kr
Sc Ti V Cr Mn Fe Co Ni Cu Zn
39 40 41 42 43 44 45 46 47 48
Rb Sr In Sn Sb Te I Xe
Y Zr Nb Mo Tc Ru Rh Pd Ag Cd
La- 72 73 74 75 76 77 78 79 80
Cs Ba Tl Pb Bi Po At Rn
Lu Hf Ta W Re Os Ir Pt Au Hg
Ac- 104 105 106 107 108 109 110 111 112
Fr Ra Nh Fl Mc Lv Ts Og
Lr Rf Db Sg Bh Hs Mt Ds Rg Cn

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Transition
Metals
The hard transition metals are often extracted
from their ores in their red-hot, pure, and molten
form via a process called smelting. While molten,
these metals can be precisely mixed to make
alloys, such as steels and brasses, which have
useful characteristics.
40 | ELEMENTS

Transition Metals
The largest collection of elements in the periodic table, there are
38 transition metals. Most of them have high melting and boiling
points, conduct heat and electricity well, and are easy to shape.
These metals are not as reactive as the alkali metals and alkaline
earth metals.

Hard metals
The transition metals tend to be dense Bracelet
made of gold
and hard compared to metals in other
sections of the periodic table.
They are frequently
mixed together to
make alloys, such
as steel or brass,
which are harder Precious metals
and stronger still. The four “precious” metals—gold, silver,
platinum, and palladium—are transition
metals. They are called precious because
they are rare. They stay shiny without
Strong titanium corroding, which makes them ideal for
alloy wheel crafting jewelry.

Good conductors
The elements in this group are good conductors,
which means that heat and electric currents move
through these substances easily. Silver is the best
conductor of all, but it is too expensive to use in
large amounts. Electrical and telephone wires and
Copper wires television cables are largely made from copper,
inside electrical cable which is very common.
 TRANSITION METALS | 41

Colorful compounds
Each transition metal can form a variety of colorful compounds.
Different compounds absorb different amounts of light energy, Rainbow Mountains
which produces the variations in color. This is why the Rainbow at the Zhangye
Mountains in China have multiple hues: iron oxide causes Danxia Landform
the red color, while iron sulfide results in the yellow. Geological Park
in China
42 | ELEMENTS

21
Scandium Sc Titanium
There are very few ores that contain This metal is as tough as steel but much
significant amounts of scandium, so lighter. Titanium can be easily refined into
it is not widely used. It is also expensive: pure metal from its ore. It is mixed with
1 lb (0.45 kg) of scandium costs more aluminum to make superstrong alloys for
than $120,000. aircraft bodies and engines.

ATOMIC MASS 44.956 ATOMIC MASS 47.867

STATE Solid STATE Solid
DISCOVERY 1879 (Lars Frederik Nilson) DISCOVERY 1791 (William Gregor)

Laboratory
sample of
pure scandium The body of an
Airbus A380
superjumbo contains
about 84 tons
(77 metric tons)
of titanium.

The mineral albite,

which does not contain
titanium, grows
alongside brookite.
 TRANSITION METALS | 43

22
Ti
The mineral brookite
is a natural form of a
compound called
titanium dioxide.

Laboratory
sample of
pure titanium

Red-brown crystal of
brookite, an ore of titanium
44 | ELEMENTS

Vanadium
In ancient India, metalworkers learned
to make iron swords harder and sharper
by adding tiny amounts of vanadinite, the
main ore of vanadium. Today, 85 percent
of the pure vanadium produced is used
to make super-tough types of steel.

ATOMIC MASS 50.942

STATE Solid
DISCOVERY 1801 (Andrés
Manuel del Rio)

Red crystals of vanadinite,

an ore of vanadium
 TRANSITION METALS | 45

23 24
V Chromium Cr
Pure chromium is mixed
with steel to stop it from
rusting—producing
shiny stainless steel.
Compounds of
chromium come
in bright colors,
such as purple,
yellow, and red.

Laboratory sample
of pure chromium

ATOMIC MASS 51.996

STATE Solid
DISCOVERY 1798 (Nicholas
Louis Vauquelin)

25
Laboratory
sample of
Manganese Mn
pure vanadium When pure, manganese
crystals is a gray metal that is
hard and brittle. It
is mixed with silicon
into steel to harden
it. This tough
steel can be
used to make
Vanadium does tank armor.
not change shape,
even when hot, so it Chunk of
is used to build the rhodonite, an ore
latest nuclear of manganese
fusion reactors.
ATOMIC MASS 54.938
STATE Solid
DISCOVERY 1774 (Johan Gottlieb Gahn)
46 | ELEMENTS

26
Iron Fe
Oxygen, silicon, and aluminum are more ATOMIC MASS 55.845
common than iron in rocks on Earth’s STATE Solid
surface, but it is iron that makes up around
35 percent of Earth’s mass. Most of it is DISCOVERY Around 3500 bce
found in the planet’s core, which is a ball
made of hot iron and nickel, nearly
3,100 miles (5,000 km) wide.

An iron-rich compound
in human blood
called hemoglobin
transports oxygen
around the body.

Chunk of pure
iron refined in
a laboratory
 TRANSITION METALS | 47

◀ Cobalt compounds
create the distinctive blue
coloring in fine china.
FOCUS ON…
COBALT
Cobalt and its compounds
have many uses, such as ▶ Like iron and
strengthening steel and nickel, cobalt is used
making paints. in strong magnets.

27
Cobalt Co
This metal’s name comes from the German word “kobold,”
which means “goblin” (a mischievous spirit). Medieval miners
would often mistake its poisonous ores as a source of the
precious metal silver—making them very ill.

ATOMIC MASS 58.933

STATE Solid
DISCOVERY 1739 (Georg Brandt)

Purple-pink crystals
of cobaltocalcite,
an ore of cobalt

Laboratory-refined
disk of pure cobalt
People have been painting with the
colorful oxides of iron for more than

20,000 years
 CAVE PAINTING
This bison was painted on a wall of the Cave of
Altamira in Spain around 15,000 bce. Its red color is
from ocher (a mixture of iron oxide, clay, and sand).
Many other oxides of transition metals have been
used as sources of color since prehistoric times.
50 | ELEMENTS

28
Nickel Ni
Along with iron and cobalt, nickel is used to ATOMIC MASS 58.693
make strong magnets, such as those found STATE Solid
in electric motors. It is also used in many
alloys, protecting them from corrosion. The DISCOVERY 1754 (Axel Fredrik Cronstedt)
US 5 cent coin is made of an alloy of
copper and nickel.

A high concentration
of nickel gives this
mineral its green color.

Crystals of
garnierite, an
ore of nickel
 TRANSITION METALS | 51

29
Copper Cu
This distinctly red metal
is one of the few metallic
elements to be found
pure in nature. It was
one of the first metals
to be used by humans.
Mixing it with tin forms
a tough alloy called
bronze, which has been
in use for more than
5,000 years.
Pellets of pure copper
refined in a laboratory

ATOMIC MASS 63.546

STATE Solid
DISCOVERY Prehistoric

30
Zinc Zn
Although this element was
not recognized until the
18th century, compounds
of zinc have been in use for
many centuries. Calamine
lotion, for example, contains
zinc oxide and is an ancient
recipe for soothing itches.

ATOMIC MASS 65.38

STATE Solid
DISCOVERY 1746
(Andreas Marggraf)

Laboratory sample
of pure zinc
 39
Yttrium Y
The metal yttrium is more common in moon rocks
than in Earth’s crust. It has a number of high-tech
uses, such as in the making of camera lenses.
Yttrium-rich crystals can also make laser
beams powerful enough to cut through metal.

ATOMIC MASS 88.906

STATE Solid
DISCOVERY 1794 (Johan Gadolin)

Laboratory sample
of pure yttrium

40
Zirconium Zr
This metal is named after the mineral zircon,
a golden-brown crystal that is a natural form
of the compound zirconium silicate. Some
zircon crystals found in Australia are nearly
4.4 billion years old, making them some
of the oldest crystals on the planet.

ATOMIC MASS 91.224

STATE Solid
DISCOVERY 1789 (Martin
Heinrich Klaproth)

Laboratory-refined bar
of pure zirconium
 TRANSITION METALS | 53

41
Niobium Nb
An alloy of this rare metal is used to make wires that provide
electricity to very powerful magnets. The magnets in the
16.78-mile- (27-km-) long Large Hadron Collider (LHC), Shiny
the world’s largest particle accelerator, use 1,323 tons metallic
surface
(1,200 metric tons) of niobium alloy. Physicists use
this machine to make atoms collide with each
other at high speeds.

ATOMIC MASS 92.906

STATE Solid
DISCOVERY 1801 (Charles
Hatchett), 1844 (Heinrich
Rose), 1864 (Christian
Blomstrand)
Laboratory-refined rods
of pure niobium

42
Molybdenum Mo
Molybdenite, the main mineral of
molybdenum, is similar in its dark
color to galena, an ore of lead.
Ancient metalworkers mistook
molybdenite for galena and named
it “molybdos,” which is Greek for
“lead.” Pure molybdenum is
actually much harder than lead
and is used to strengthen alloys.

ATOMIC MASS 95.95

STATE Solid
DISCOVERY 1781
(Peter Jacob Hjelm)
Molybdenite, an
ore of molybdenum
54 | ELEMENTS

43 44
Technetium Tc Ruthenium Ru
The atoms of this highly radioactive Ruthenia, the Latin name
element are very unstable and break for Russia, inspired this
down quickly. Technetium was named rare element’s name.
after “teknetos,” the Greek word for Ruthenium is used in
“artificial.” It is the first artificial element turning coal into the
to have been created. liquid fuel petroleum,
in X-ray machines,
ATOMIC MASS (98)
and in making solar
cells (devices that turn
STATE Solid sunlight into electricity).
DISCOVERY 1937 (Carlo Perrier and Laboratory-
Emilio Segrè) refined
ATOMIC MASS 101.07 crystals of
STATE Solid pure ruthenium

Foil DISCOVERY 1808 (Jedrzej Sniadecki),

of pure 1825 (Gottfried Osann), 1844 (Karl
technetium Karlovich Klaus)

46
Palladium Pd
This precious metal is added in
small amounts to gold to make
white-gold jewelry. A compound
called palladium chloride is an
ingredient in sensors that detect
levels of poisonous carbon
monoxide gas.

ATOMIC MASS
106.42
STATE Solid
DISCOVERY
1803 (William
Hyde Wollaston)
Piece of
pure palladium
 TRANSITION METALS | 55

45
Rhodium Rh
The element rhodium is one of the rarest ATOMIC MASS 102.906
elements of all. The total annual production STATE Solid
of rhodium across the world is a mere
33 tons (30 metric tons). This shiny metal DISCOVERY 1803 (William Hyde Wollaston)
is used in a car’s catalytic converter,
a device that removes
poisonous gases from
the exhaust fumes.
The sand on the banks
of the Ural River in
Central Asia is a major
source of rhodium.

The mineral
forms as
golden
needles.

Golden crystals
of millerite, an
ore of rhodium
56 | ELEMENTS

FOCUS ON…
SILVER
Silver is the most
common precious ▲ Thin, edible ▲ Silver nitrate mixed ▲ Silver is commonly
metal and has a silver foil is used to with water is used as used in jewelry
wide range of uses. decorate sweets. a gentle antiseptic for such as necklaces,
cuts and scrapes. bangles, and rings.

47
Silver Ag
Like the precious metals gold, platinum, ATOMIC MASS 107.868
and palladium, silver is found pure in STATE Solid
nature. It stays shiny for a while, but
unlike other precious metals, DISCOVERY Around 3000 bce
silver reacts slowly with
traces of sulfur in the
air to create a This silver was left
black tarnish. behind when hot,
mineral-rich water
trickled through rocks.

Twists of silver
on quartz
 TRANSITION METALS | 57

48
Cadmium Cd
During the refining and production of
zinc from its ore, cadmium is extracted
as an impurity. This metal was once used
to make vibrant yellow paint, but it is no
longer used as it is now known to be
highly toxic. Today, cadmium is used
mainly in rechargeable batteries.

ATOMIC MASS 112.414

STATE Solid
DISCOVERY 1817
(Friedrich Stromeyer)
This mineral is mainly composed
of cadmium sulfide.

Greenockite, an ore of cadmium

72
Hafnium Hf
Chemists knew there was a gap in the ATOMIC MASS 178.49
periodic table, underneath zirconium, but STATE Solid
couldn’t find the missing element for many
years. Hafnium was eventually found DISCOVERY 1923 (George Charles
in crystals of a mineral called zircon. de Hevesy and Dirk Coster)
It was discovered to be nearly
identical to zirconium,
which was also present
in the crystals.

Laboratory
sample of
pure hafnium
58 | ELEMENTS

73
Tantalum Ta
This transition metal gets its name from Tantalus, a
figure in Greek mythology. Tantalum does not
corrode easily and is used to make capacitors,
which are tiny devices for storing electricity
inside cell phones and tablets.

ATOMIC MASS 180.948

STATE Solid
DISCOVERY 1802 (Anders
Gustav Ekeberg)

Microlite is so named
because it forms tiny crystals.

Dark crystals of microlite,

an ore of tantalum, in rock

74
Tungsten W
This element has the highest melting point
of any metal: it melts into a liquid at a
scorching 6,177.2°F (3,414°C). Due to
its heat-resistant properties, tungsten
is used to make light bulb filaments,
which can get very hot when a bulb
is in use. This element is also mixed
with carbon to make tungsten
carbide, a compound used to
harden metal tools.

ATOMIC MASS 183.84

STATE Solid
DISCOVERY 1783 (Juan and
Fausto Elhuyar)
Ferberite, an ore of tungsten
 TRANSITION METALS | 59

75 77
Rhenium Re Iridium Ir
Liquid rhenium will not boil until it is One of Earth’s rarest elements, iridium
at 10,094°F (5,590°C), which is about is found in a thin layer of clay in the
the same temperature as the surface planet’s crust, and is especially seen in
of the sun. This metal has the highest the Badlands of South Dakota. Scientists
boiling point of any element. Rhenium is think it was distributed by the meteorite
used to make heat-resistant superalloys that made the dinosaurs extinct.
for X-ray machines and the exhaust
nozzles for jet fighters and rockets. ATOMIC MASS 192.217
STATE Solid
ATOMIC MASS 186.207
DISCOVERY 1803 (Smithson Tennant)
STATE Solid
DISCOVERY 1925 (Walter Noddack,
Ida Tacke, and Otto Berg)

76
Osmium Os
0.06 cubic in (1 cubic cm) of osmium is
more than 22 times heavier than the same
amount of water. This transition metal
is the densest element in the world.
It can be used by police investigators
to find clues at a crime scene. One
of its compounds, osmium oxide,
mixes well with oil so it is used in
the search for fingerprints.

Pellet of pure osmium

refined in a laboratory

ATOMIC MASS 190.23

STATE Solid
DISCOVERY 1803
(Smithson Tennant)
60 | ELEMENTS

78
Platinum Pt
The name platinum comes from the ATOMIC MASS 195.084
Spanish word “platina,” which means “little STATE Solid
silver.” Although the Maya civilization in
South America had used this metal for DISCOVERY Around 700 bce
centuries, it was only in the 1750s that
Spanish explorers brought it to Europe.
This metal has a
high melting point of Platinum is commonly
3,214.8°F (1,768.2°C). used in catalytic
converters, which are
devices in cars that
reduce toxic
exhaust fumes.

Laboratory-refined nugget
of pure platinum
 TRANSITION METALS | 61

FOCUS ON…
GOLD
This metal has a ▲ Gold coins, such as ▲ The most reliable ▲ The domes of some
wide range of this Byzantine one from microchips have gold buildings, such as
modern practical around 600 ce, have connections that rarely Brunei’s Jame’Asr
applications. been used as currency corrode or fail. Hassanil Bolkiah Mosque,
for a long time. are covered in gold.

79
Gold Au
This precious metal is very soft
and easy to shape. 0.06 cubic in
(1 cubic cm) of gold can be drawn
into a wire 540 ft (165 m) long without
breaking, or hammered into 10 sq ft
(1 sq m) of foil. Because of this,
gold has been used extensively
in making jewelry for thousands
of years.

ATOMIC MASS 196.967

STATE Solid
DISCOVERY Around 3000 bce

Nuggets such as
this one are rare
as most gold is
found as dust
mixed into rocks.

Nugget of pure gold

A spacesuit’s reflective
visor includes a layer of gold

0.000002 in
(0.00005 mm)
thick to protect the astronaut’s eyes
 GOLDEN VIEW
The transition metals are very shiny when clean as
their atoms reflect light and other invisible rays. Gold,
one of the shiniest transition metals, is used to coat
the helmet visors of spacesuits to protect astronauts
from the sun’s dangerous rays.
64 | ELEMENTS

80
Mercury Hg
The only metal that is liquid at room temperature,
mercury melts at -37.9°F (-38.8°C) and is solid
below this temperature. Pure mercury is easily
refined by heating its minerals, such as cinnabar.
It is highly poisonous and its use is limited.

ATOMIC MASS 200.592

STATE Liquid
DISCOVERY Around 1500 bce
Chunk of cinnabar,
an ore of mercury
The chemical symbol
for mercury, Hg, comes
from “hydrargyrum,” a
Latin term that means
“water silver.” Liquid form of
pure mercury
 TRANSITION METALS | 65

104 106
Rutherfordium Rf Seaborgium Sg
The artificial element Rutherfordium was This metal was named after the American
named after New Zealand chemist Baron chemist Glenn T. Seaborg, who is credited
Ernest Rutherford, who studied and with identifying and studying 10 artificial
explained the structure of an atom. This elements. Seaborgium is radioactive
element can be made by and its atoms break up after only a
smashing together atoms few minutes.
of neon and plutonium.
ATOMIC MASS (269)
ATOMIC MASS (267) STATE Solid
STATE Solid DISCOVERY 1974
DISCOVERY 1964 (team led by
(team led by Albert Ghiorso)
Georgy Flerov),
1969 (team led by
Albert Ghiorso)
Ernest Rutherford
Glenn T.
Seaborg
105
Dubnium Db
Element 105 was discovered by two
independent teams in Russia and the
US. Dubnium was eventually named
after the Russian city of Dubna, which
is home to the Joint Institute for Nuclear
Research (JINR), the center of atomic
research in the country.

ATOMIC MASS (268)

STATE Solid
DISCOVERY 1968 (team led by Georgy
Flerov), 1970 (team led by Albert Ghiorso)
66 | ELEMENTS

107 109
Bohrium Bh Meitnerium Mt
The Danish scientist Niels Bohr was one This element was named for Lise Meitner,
of the first to figure out how protons, an Austrian-Swedish scientist who was
neutrons, and electrons are arranged one of the leaders of the team that
inside atoms. Element 107, made by discovered the nuclear fission chain
fusing chromium atoms reaction in uranium. This is the process
with bismuth, is named that drives nuclear power and causes
after him. nuclear bombs to explode. While her
name was left out of the Nobel Prize
ATOMIC MASS (270)
awarded for this discovery, she eventually
got an element named after her.
STATE Solid
DISCOVERY 1981 ATOMIC MASS (278)
(team led by
Peter Armbruster STATE Solid
and Gottfried DISCOVERY 1982 (team led by Peter
Münzenberg) Armbruster and Gottfried Münzenberg)
Niels Bohr

108
Hassium Hs
The atoms of hassium are so radioactive
that they decay in a matter of seconds,
so the only way scientists can study this Bust of Lise
element is by producing it artificially. Meitner in
Hassium is thought to be a solid metal Berlin, Germany
but so far not enough atoms have been
made all at once for this to be confirmed.
This element is named after Hesse, the
German state where it was first made.

ATOMIC MASS (269)

STATE Solid
DISCOVERY 1984 (team led by Peter
Armbruster and Gottfried Münzenberg)
 TRANSITION METALS | 67

110 111
Darmstadtium Ds Roentgenium Rg
The atoms of this element break down This transition metal is made by fusing
quickly, but it is thought to have similar bismuth with nickel. It is a very radioactive,
properties to platinum. Many teams tried short-lived metal. Roentgenium is named
to make it, but its creation was first after the German physicist Wilhelm Conrad
confirmed in the Society for Heavy Ion Röntgen, the discoverer of X-rays.
Research in Darmstadt, Germany, before
it was named after that city. Darmstadtium ATOMIC MASS (280)
is made by smashing nickel atoms into
those of lead. STATE Solid
DISCOVERY 1994
ATOMIC MASS (281) (team led by Peter
Armbruster and
STATE Solid Gottfried Münzenberg)
DISCOVERY 1994 (Sigurd Hofmann, Peter
Armbruster, and Gottfried Münzenberg) Wilhelm Conrad
Röntgen

112
Copernicium Cn
In 1543, the Polish astronomer Nicolaus
Copernicus theorized that Earth revolves
around the sun. Copernicium was named
in his honor. This element is made by firing
zinc atoms at lead. Only tiny amounts have
been made so far and it has been suggested
that a large sample of this metallic element
might even be a gas at room temperature.

ATOMIC MASS (285)

STATE Solid
DISCOVERY 1996 (team led by
Sigurd Hofmann)

Statue of Nicolaus Copernicus

in Olsztyn, Poland
 H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

La-
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Lu

Ac-
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Lr
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Lanthanides
The metals in this series are relatively common
on Earth—and very useful in technology—but
notoriously difficult to separate from one another.
Here, a sliver of lanthanum nitrate, showing off
a rainbow of colors under a microscope, has
been extracted from a complex mineral filled
with many other lanthanides.
70 | ELEMENTS

Lanthanides
Normally shown as a strip of elements along the bottom of the
periodic table (along with the actinides), this series of metals is
found in the sixth period (row) between Group 2 and the transition
metals. The lanthanides are named after lanthanum, the first
element in this series.

Swedish discovery
The lanthanides have very similar chemical and physical properties,
and that made it hard for chemists to tell them apart. The
discovery of the mineral gadolinite in 1787, in the village of
Ytterby, Sweden, was a breakthrough. Gadolinite can be
broken down into various lanthanides, and after a century
of studying it, nine lanthanides were eventually found.
Four of these—erbium, terbium, ytterbium, and
yttrium—were named after Ytterby.
Black crystals of
gadolinite in rock

Rare earths
Because they were found combined together in various
minerals in Earth’s crust, the lanthanides were called “rare
earth metals” and were thought to be hard to find. Despite
the name, lanthanides are quite common. They are
found in low concentrations through all kinds of rock,
and are seldom seen in large quantities in one place.

This mineral contains traces

of almost all lanthanides.

Chunk of monazite, an
ore of many lanthanides
 LANTHANIDES | 71

Magnetic elements
Several lanthanides are very magnetic, and tiny amounts of them
are added to iron and nickel magnets to boost their strength.
Lanthanide-rich magnets are used to read and write computer
memory and to make pickups—devices in electric guitars that
convert the vibrations of the strings into electric signals.
The pickups on this guitar use magnets
made of the lanthanide samarium.
Electric guitar

Light emission
Lanthanides are crucial in the production of
colored light in light-emitting diodes (LEDs).
Blue LEDs get their colors from chemicals
containing europium, while green LEDs
use chemicals with terbium.

Blue LEDs glow on

Dubai’s Meydan Bridge
72 | ELEMENTS

57
Lanthanum La
Following its discovery, it took almost 100 years
to figure out how to make a pure sample of this
lanthanide. Pure lanthanum is used to make
clear camera lenses, and some compounds of
lanthanum are used when refining the liquid
fuel petroleum.

ATOMIC MASS 138.905

STATE Solid
DISCOVERY 1839 (Carl
Gustav Mosander)

Misch metal (an alloy

of lanthanum, cerium,
and praseodymium)
is used to produce
sparks for special
effects in films.

Lanthanum
will quickly
tarnish when
it is exposed
to air.

Laboratory
sample of
pure lanthanum
 LANTHANIDES | 73

FOCUS ON…
PRASEODYMIUM
This lanthanide metal has a
range of uses, from coloring ▲ Artificial gems, such as ▲ Praseodymium is mixed with
glass to making alloys for this cubic zirconia, are dyed magnesium to make superstrong
powerful magnets. green using praseodymium. alloys for aircraft engines.

58 59
Cerium Ce Praseodymium Pr
Of the rare earth elements, cerium is the The name of this metal, which means
most common. It is even more common in “green twin” in Greek, refers to how pure
Earth’s rocks than copper or lead. Cerium samples of praseodymium will transform
is used to make touchscreens on devices, into a flaky green chemical when left in the
some batteries, and glass polish. air. Glasses tinted with praseodymium
Black crystals have a yellow color and make it
of allanite, an easier to see in dark conditions.
ore of cerium
ATOMIC MASS 140.908
STATE Solid
DISCOVERY 1885
(Carl Auer
von Welsbach)

ATOMIC MASS 140.116

STATE Solid Chunk of
DISCOVERY 1803 (Baron Jöns Jacob monazite, an ore
Berzelius and Wilhelm Hisinger), of praseodymium
1803 (Martin Klaproth)
74 | ELEMENTS

60
Neodymium Nd Europium
When mixed with iron and boron, Although it is named after the continent of
neodymium makes the most powerful Europe, europium is mainly found in rocks
magnets in the world, which can lift in American and Chinese mines. Europium
objects up to 1,000 times their own weight. compounds glow red in ultraviolet light,
They are known as NIB magnets. so they are added to bank notes, including
euro notes, to prove they are authentic.
ATOMIC MASS 144.242
Laboratory sample
STATE Solid of pure europium
DISCOVERY 1885 (Carl Auer
von Welsbach)
Laboratory
sample of pure
neodymium

61
Promethium Pm
Every form of this lanthanide is highly
radioactive. Any natural promethium
that was in Earth’s rocks broke up billions
of years ago. However, new promethium
atoms are constantly being formed
when the atoms of heavier elements
break apart—only for the new
promethium atoms to also split up.
Scientists can make small amounts
of this element artificially.

ATOMIC MASS (145)

STATE Solid
DISCOVERY 1945 (Jacob A. Marinsky,
Lawrence E. Glendenin, and
Charles D. Coryell)
 LANTHANIDES | 75

63 62
Eu Samarium Sm
ATOMIC MASS 151.964 The small but powerful electric motors that
STATE Solid power some electric aircraft use samarium
magnets. Samarium is also used
DISCOVERY 1901 (Eugène-Anatole in some lasers and in
Demarçay) nuclear reactors.
The yellowish metal
goes black when
exposed to air.

Laboratory sample of pure samarium

ATOMIC MASS 150.36

STATE Solid
DISCOVERY 1879 (Paul-Émile Lecoq
de Boisbaudran)

64
Gadolinium Gd
The Finnish chemist Johann Gadolin
inspired the names of this lanthanide and
its ore, gadolinite. Gadolinium
tarnishes quickly when
in contact with air.

ATOMIC MASS 157.25

STATE Solid
DISCOVERY 1880
(Jean Charles Galissard
de Marignac)

Laboratory sample
of pure gadolinium
76 | ELEMENTS

65
Terbium Tb
Pure terbium is soft enough
to cut with a knife. Some of
its compounds are used to
line mercury lamps. When
electrified, mercury vapour
inside these lamps gives off
ultraviolet light, which turns
bright yellow due to terbium.

ATOMIC MASS 158.925

STATE Solid
DISCOVERY 1843 (Carl
Gustav Mosander)

In the 19th century,

scientists got confused
between terbium
and erbium and
accidentally switched
their names.

Laboratory sample
of pure terbium
 LANTHANIDES | 77

66
Dysprosium Dy
Compared to other lanthanides,
this element reacts more easily
with oxygen and water. Its
name means “hard to get at”;
the metal was purified for the
first time only in the 1950s.

ATOMIC MASS 162.5

STATE Solid
DISCOVERY 1886
(Paul-Émile Lecoq
de Boisbaudran)

Laboratory sample of
pure dysprosium

67
Holmium Ho
The lanthanide holmium is named after the
Swedish capital Stockholm, which is called
“Holmia” in Latin. It is used in the making
of some medical lasers. Holmium lasers
are hot enough to burn through skin—
surgeons and dentists use them to
make delicate cuts that heal quicker
than traditional surgical cuts.

ATOMIC MASS 164.93

STATE Solid
DISCOVERY 1878 (Marc
Delafontaine and Louis Soret),
1878 (Per Teodor Cleve)
Black crystals of gadolinite,
an ore of holmium
78 | ELEMENTS

69
Thulium Tm
The rarest of all the lanthanides, thulium ATOMIC MASS 168.934
glows blue when invisible ultraviolet light STATE Solid
shines on it. Small X-ray machines in
ambulances use a radioactive form of DISCOVERY 1879 (Per Teodor Cleve)
the metal to produce X-rays.
Laboratory
sample of
pure thulium
 LANTHANIDES | 79

68 70
Erbium Er Ytterbium Yb
Compounds of erbium are used to This metal reacts with oxygen in the air,
create pink tints for glass and pottery. so is stored in sealed containers. Pure
Crystals containing this metal can ytterbium has several uses, including the
boost laser signals traveling through strengthening of steel.
long-distance Internet cables.
ATOMIC MASS 173.045
ATOMIC MASS 167.259 STATE Solid
STATE Solid DISCOVERY 1878 (Jean Charles
DISCOVERY Galissard de Marignac)
1843 (Carl
Gustav
Mosander)

Laboratory
sample of
pure erbium

71
Lutetium Lu
The final member of the lanthanide group is
Ytterbium
also the densest. It is mainly used to break
is easy to
up complex chemicals hammer into
in crude oil into smaller thin sheets.
and more useful
substances.

Laboratory
sample of
Laboratory
pure lutetium
sample of
pure ytterbium
ATOMIC MASS 174.967
STATE Solid
DISCOVERY 1907 (Georges Urbain),
1907 (Charles James), 1907 (Carl Auer
von Welsbach)
H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

La-
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Lu

Ac-
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Lr

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

89 90 91 92 93 94 95 96 97 98 99 100 101 102 103

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Actinides
Elements in the actinide series, such as uranium,
are unstable and radioactive, and they release
heat as they break down. The heat released by
uranium atoms can be used for generating power.
Here, fuel rods packed with uranium are used in
nuclear reactors.
82 | ELEMENTS

Actinides
This series of metals appears along the bottom of the periodic
table, underneath the lanthanides. The group gets its name from
actinium, the first member in the series. The heaviest naturally
occurring elements of all, such as thorium and uranium, are
actinides, along with many elements created artificially.

Radioactivity
Actinides are highly radioactive
elements. Given enough time, the
atoms of all these elements will break
up and decay away. While thorium and
uranium are the most stable and will
last for billions of years, some other
actinides have atoms that break up in
a fraction of a second. Actinides are
used as nuclear fuels for making
electricity. Nuclear reactor complexes
include hazardous areas with radiation
warning symbols that alert people of
the dangers within.

Radioactivity blasting from

the uranium rod creates a
blue glow. The heat from
the fuel makes steam for
generating electricity.

Nuclear rod
heating water Radiation symbol
Naming elements
The two most common actinides, thorium and uranium, were
discovered much earlier than the others and were named after
Thor (the Norse god of thunder) and the planet Uranus, which
was a recent discovery when uranium was identified. Most of the
actinides were discovered in recent years and many of them were
The planet
named after famous scientists—curium, after Marie Curie—or Uranus, which
places, such as californium, after the state of California. uranium was
named after

Artificial elements
Of the actinides, only thorium and uranium are
common enough to be refined from ores. Some other
actinides do exist in nature but in tiny amounts.
Many actinides are created artificially in a particle
accelerator, such as the linear accelerator shown
here, which smashes atoms together to make
bigger, heavier elements. They are also made
in nuclear reactors as uranium atoms decay.

Super Heavy Ion Linear Accelerator

in Lawrence Berkeley National
Laboratory, California
84 | ELEMENTS

Actinium
This radioactive metal appears in tiny amounts
wherever there is uranium present. The uranium
breaks down into actinium, which over time
splits itself into radon gas, giving out a form
of radiation called alpha particles.

ATOMIC MASS (227)

STATE Solid
DISCOVERY 1899 (Andrew Debierne)
 ACTINIDES | 85

89 90
Ac Thorium Th
Named after Thor, the Norse
Autunite god of thunder, thorium is the
crystals range most common radioactive
in color from metal in Earth’s rocks. The
bright yellow Actinium’s heat from thorium’s decay
to green.
radioactivity makes deep inside Earth keeps the
it emit an eerie blue planet warm, along with
glow in the dark. the sun’s heat.

ATOMIC MASS 232.038

STATE Solid
DISCOVERY 1829 (Baron
Chunk of Jöns Jacob Berzelius)
autunite, Piece of thorianite,
an ore of an ore of thorium
actinium

91
Protactinium Pa
The name of this highly
radioactive metal means
“before actinium,”
because uranium
decays first into
protactinium, which
then breaks down
into actinium.

Green crystals of
torbernite, an ore of
protactinium, in rock

ATOMIC MASS 231.036

STATE Solid
DISCOVERY 1913 (Kasimir Fajans and
Otto Göhring)
86 | ELEMENTS

92
Uranium U
This heavy metal was the first
substance to be identified as
radioactive, a discovery made
by the French physicist Henri
Becquerel in 1896. It is used in
the making of nuclear bombs
and as fuel for nuclear reactors,
which generate electricity.

ATOMIC MASS 238.029

STATE Solid
DISCOVERY 1789 (Martin
Heinrich Klaproth), 1841
(Eugène Peligot)

Chunk of pure uranium

93
Neptunium Np
Sitting next to uranium on the periodic table is
another radioactive element called neptunium.
This actinide was named after the planet
Neptune. Neptunium was first discovered
after being made inside a nuclear reactor.
It is used mainly in scientific research.

ATOMIC MASS (237)

STATE Solid
DISCOVERY 1940 (Edwin McMillan and
Philip Abelson)

Piece of uraninite, an ore that

has tiny traces of neptunium
 ACTINIDES | 87

FOCUS ON…
PLUTONIUM
Isotopes (forms) of
plutonium are radioactive ▲ Deep space probes, ▲ Plutonium was used ▲ One form of
and produce heat. This such as Voyager 1, use in early nuclear bombs – plutonium is used
is converted to electricity plutonium batteries as one such bomb was used as nuclear fuel for
for various uses. a source of power. on Japan in World War II. generating electricity.

94
Plutonium Pu
The actinide plutonium was named after Pluto, the
dwarf planet. It was the first artificial element to be
manufactured in large amounts. It can be created
from uranium in nuclear reactors.

ATOMIC MASS (244)

STATE Solid
DISCOVERY 1940 (team led by
Glenn T. Seaborg)

“Fat Man,” the

nuclear bomb dropped
over Nagasaki, Japan,
in 1945, contained
about 14.3 lb (6.5 kg)
of plutonium fuel.

Chunk of uraninite,
an ore of plutonium
88 | ELEMENTS

95 97
Americium Am Berkelium Bk
Scientists decided to name americium The first particle accelerators were built
after North America, where it was first in the University of California in Berkeley.
made. Some smoke detectors use tiny It was here that this metal was first
amounts of this element, as its radioactivity created, so it was named after the
allows an electric current to pass through town. Scientists made berkelium by
the air between two sensors in the device. smashing atoms of helium and americium
Any smoke blocking the current causes together. This element is used only to
the detector to sound an alarm. make even heavier elements.

ATOMIC MASS (243) ATOMIC MASS (247)

STATE Solid STATE Solid
DISCOVERY 1944 (team led by DISCOVERY 1949 (team led by
Glenn T. Seaborg) Glenn T. Seaborg)
 ACTINIDES | 89

99
Einsteinium Es
In 1952, a new kind of powerful
nuclear weapon called the hydrogen
bomb (H-bomb) was tested. After
the explosion, scientists studying the
debris found around 200 atoms of a
new actinide. They named this new
element after the German-American
physicist Albert Einstein.

ATOMIC MASS (252)

STATE Solid
DISCOVERY 1952–5 (team led by
Albert Ghiorso)

Albert Einstein

96 98
Curium Cm Californium Cf
The actinide curium was named after the This element was named after California,
Polish-French scientist Marie Curie and the US state where it was first made.
her husband, the French scientist Pierre Californium is a raw material used for
Curie—the discoverers of the element making very heavy elements, such as
radium. Rovers (remote-controlled robot oganesson. It is one of the world’s
vehicles used for exploration) on Mars use most expensive substances: a gram of
curium to shine X-rays on rock samples, californium costs $27 million. This is
revealing what is in them. because it is difficult to produce this highly
radioactive element, making it rare.
ATOMIC MASS (247)
STATE Solid ATOMIC MASS (251)
DISCOVERY 1944 (team led by STATE Solid
Glenn T. Seaborg) DISCOVERY 1950 (Stanley Thompson;
Kenneth Street, Jr.; Albert Ghiorso; and
Marie Curie in Glenn T. Seaborg)
her laboratory
90 | ELEMENTS

100
Fermium Fm
The American physicist Albert Ghiorso
and his colleagues found fermium
in the debris left behind by the
first successful hydrogen bomb
explosion in 1952, conducted by
the US. This artificial element
has no use apart from in research.

ATOMIC MASS (257)

STATE Solid
DISCOVERY 1953 (team The explosion also
produced einsteinium,
led by Albert Ghiorso) another element that was
unknown at the time.

Mushroom cloud from the 1952

hydrogen bomb test, named “Ivy Mike”

101
Mendelevium Md
This element is named after the Russian chemist
Dmitri Mendeleev, who created the periodic table.
It has no commercial uses. Artificial elements such
as mendelevium are created in a machine called
a particle accelerator. This one can be made by
smashing together the atoms of bismuth and
argon until they fuse into a single large
mendelevium atom.

ATOMIC MASS (258)

STATE Solid
DISCOVERY 1955 (team led by
Albert Ghiorso)

Statue of Dmitri Mendeleev

in Tobolsk, Russia
 ACTINIDES | 91

102 103
Nobelium No Lawrencium Lr
Scientists in California discovered The American physicist Ernest Lawrence,
nobelium by smashing together atoms of inventor of the cyclotron (a type of
curium and carbon in a particle accelerator. particle accelerator), was the inspiration
It is named after Alfred Nobel, the Swedish behind the name of this actinide. Only
chemist who invented dynamite. a few atoms of this radioactive element
have been made.
ATOMIC MASS (259)
STATE Solid ATOMIC MASS (262)
DISCOVERY 1956 (team led by STATE Solid
Georgy Flerov), 1958 (team led DISCOVERY 1958 (team led by
by Albert Ghiorso) Albert Ghiorso), 1965 (team led
by Georgy Flerov)

Ernest
Lawrence
Alfred Nobel
stands next
to an early
cyclotron
 H He

5
Li Be C N O F Ne
B
13
Na Mg Si P S Cl Ar
Al
31
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ge As Se Br Kr
Ga
49
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd Sn Sb Te I Xe
In
La- 81
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Pb Bi Po At Rn
Lu Tl
Ac- 113
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Fl Mc Lv Ts Og
Lr Nh

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Boron Group
The boron group has a wide range of elements—from
the ultra-hard semi-metal boron to soft, heavy metals
such as thallium—with no obvious features shared by
the members. By far the most common of the metals
is aluminum, which is used to build strong structures,
such as these turbine blades from a jet engine.
94 | ELEMENTS

Boron Group
Boron is a semi-metal (element
with properties of a metal and
a nonmetal), while most other
members of this group are metals.
The properties of the artificial
element nihonium, however, are
not yet known. Compared to other
metals, the boron group metals
are not very reactive, and are
sometimes referred to as poor
metals because they melt at
low temperatures.

Boron creates links

between the glue
molecules so it stays
in a single lump.

Making slime
One of the most important
compounds of boron is borax, a
chemical that also contains sodium and
oxygen. This white material, used in cleaners
and other common products, is mined in desert
areas. When added to glue and water, it makes
slime, which is a gooey toy that flows like a liquid
but bounces like rubber.

Stretched slime
 BORON GROUP | 95

Soft metals Aluminum atoms

make up a quarter
Most boron group metals, including of this ore.
indium, can be cut with a steel knife,
so they are not tough enough for
construction. Only aluminum is suitable
for building structures. By contrast,
boron—the sole nonmetal—is one Bauxite, a mineral
of the hardest elements of all. ore of aluminum

Natural compounds
The elements in the boron group are never
found pure in nature, despite not being very
reactive. All of them, like members of some
other groups, have to be purified from ores.
Aluminum is a very common ingredient in
minerals, while the other elements are
considerably rarer.

Pure indium mold cast

in a laboratory

Conducting metals
The metallic members of this group are all good
conductors of electricity, especially aluminum.
Because aluminum is more lightweight than
other conducting metals, it is often used in
overhead electricity cables. Semi-metallic
boron, however, is a good insulator when
pure, and blocks electric currents.

Overhead cables
of aluminum
96 | ELEMENTS

5
Boron B
The first semi-metal
in the periodic table, pure
boron has a slight shine to
it, like a metal, but unlike
metals it does not conduct
electricity very well. Boron
and its compounds have Boron and carbon
many uses, including in form boron carbide,
the making of detergents, one of the hardest
LCD screens, and even known materials
tank armor. on the planet.

ATOMIC MASS 10.81

STATE Solid
DISCOVERY 1808
(Louis-Josef Gay-Lussac
and Louis-Jacques Thénard),
1808 (Sir Humphry Davy)

Kernite, an Laboratory sample

ore of boron of pure boron
FOCUS ON…
ALUMINUM
This shiny metal can be
found in many everyday ▲ Cans made of ▲ Aluminum is both ▲ Fire-protection
objects, from cans to pure aluminum are lightweight and strong suits have an
sports equipment. easy to recycle. and is used to make aluminum coating
tennis rackets. to reflect heat.

13
Aluminum Al
Despite being the most common metal in Earth’s
rocks, pure aluminum is hard to separate
from its minerals. After it was first identified,
it took a century to figure out how to
make pure aluminum in large
amounts. Now it is the
second-most utilized metal
on Earth, after iron.

ATOMIC MASS 26.982

STATE Solid
DISCOVERY 1827
(Friedrich Wöhler)

This blue-green
ore contains
aluminum,
phosphorus,
and oxygen.

Chunk of green
variscite, an
ore of aluminum
98 | ELEMENTS

31
Gallium Ga
With a melting point of just 84°F (29°C), ATOMIC MASS 69.723
the warmth of a person’s hand is enough STATE Solid
to make this shiny metal melt. A liquid
alloy called galinstan, which is used DISCOVERY 1875 (Paul-Émile Lecoq
in medical thermometers, is made by de Boisbaudran)
mixing tin and indium with gallium.

Cube of
melting gallium
 BORON GROUP | 99

49 81
Indium In Thallium Tl
When electricity is passed through indium This soft metal takes its name from the
atoms they glow an indigo color, which Greek word “thallos,” which means “green
is where the metal gets its name from. shoot or twig,” because it burns with a
Indium is used to make very thin bright green flame. Pure thallium is very
electrical wires that run toxic: if ingested, it causes stomach pains
through the touchscreens and makes hair fall out.
of cell phones.
ATOMIC MASS 204.38
Black crystals
of sphalerite, STATE Solid
an ore of indium DISCOVERY 1861
(William Crookes)
ATOMIC MASS 114.818
STATE Solid Laboratory sample
of pure thallium in
DISCOVERY 1863 (Ferdinand
an airless vial
Reich and Hieronymous Richter)

113
Nihonium Nh
Pure
This is the only artificial element made in thallium is
Japan. It was named after the Japanese stored
name for Japan, “Nihon.” Nihonium forms away from
when moscovium atoms break apart, but air to keep
it from
it can also be made by smashing bismuth
tarnishing.
and zinc atoms together. It is highly
radioactive, and is used only in research.

ATOMIC MASS (286)

STATE Solid
DISCOVERY 2004 (team led by
Kosuke Morita)
 H He

6
Li Be B N O F Ne
C
14
Na Mg Al P S Cl Ar
Si
32
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga As Se Br Kr
Ge
50
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sb Te I Xe
Sn
La- 82
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Bi Po At Rn
Lu Pb
Ac- 114
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Mc Lv Ts Og
Lr Fl

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Carbon
Group
Atoms of carbon and the other members of this group
can bond to four other atoms at once. As a result,
these elements form a very wide range of compounds
with complex molecules. These compounds include
silicon dioxide, which is present with other elements in
types of glass. Here, a glass vase is made in a furnace.
102 | ELEMENTS

Carbon Group
This group of elements is named after the first element in it,
carbon. The carbon group is the first in the periodic table to
contain metals, semi-metals, and a nonmetal—most of which
have played a significant role in human history.

Life forms
All living organisms on Earth contain carbon.
The sugars, fats, and proteins used to build
and power a living body are all complex carbon
compounds. Plants build these compounds using
carbon dioxide taken from the air, while animals
get their supply of carbon from food.
Bronze
The metal tin was one of the earliest
metals to be purified. For thousands of
years, people have mixed tin with copper to
create an alloy called bronze, which is tougher and
more useful than either of the original metals. The
first widespread human civilizations used bronze to
make tools, statues, and weapons.
6th century bce bronze
statue of two oxen

Carbon chemistry
One carbon atom can bond to anything from one
to four other atoms, and as a result, carbon forms
a huge range of compounds. Wood, coal, oil, and
plastics are all carbon compounds. Common
fuels such as gasoline and natural gas are
also carbon-based. They release heat
when burned, and
transform into water
and carbon dioxide,
as well as carbon
Semiconducting silicon wafer monoxide, which
is a toxic gas.
Semiconductors
The impure forms of germanium and The body of this
silicon are used as semiconductors— sharpener is made of
plastic and the steel
substances that conduct electricity blade is toughened
better than insulators, but not as well with carbon grains.
as conductors. When pure, these two
This wood
semi-metals block electricity, but The pencil lead is
is made of
graphite, a form
when tiny amounts of other elements cellulose,
of pure carbon.
a carbon
are added to them, they can transmit
compound.
it. These semiconductors are used
in electronics. Pencil with
plastic sharpener
104 | ELEMENTS

6
Carbon C
All life forms on this planet are ATOMIC MASS 12.011
carbon-based. This means that the STATE Solid
basic molecules that form the cells,
tissues, and organs of all living DISCOVERY Prehistoric
organisms are a combination of
carbon and other elements. Diamond is made
from a rigid network
of carbon atoms.

Diamond
crystal

Of the roughly
10 million
compounds known
to us, 9 million
contain carbon.

Chunk of
glassy carbon
FOCUS ON…
SILICON
This semi-metal can
be used to make hard ▲ Sandpaper is made ▲ These cupcake ▲ Silica gel packets
and soft materials. from a compound of liners containing silicon are added to dry food,
silicon and carbon can be put in an oven clothes, and shoes,
called carborundum. as they are heatproof. to absorb moisture.

14
Silicon Si
After oxygen, this semi-metal is the ATOMIC MASS 28.085
second most common element in Earth’s STATE Solid
rocks. Compounds of oxygen and silicon
are called silicates and there are hundreds DISCOVERY 1824 (Baron Jöns
of different types. Around 90 percent of all Jacob Berzelius)
minerals inside rocks are silicates.

The shiny surface of

opal is from microscopic
silicate crystals.

Piece of opal,
a silicon
compound
Methane gas mixed with the water in
Siberia’s Lake Baikal gets trapped as

frozen bubbles
in the winter
 BUBBLING UNDER ICE
The gas methane is made of carbon and hydrogen, and
is present in underground reservoirs. Lighter than air,
it rises into the atmosphere in the summer from Arctic
lakes, such as Lake Baikal in Russia’s Siberia region.
In the winter, the surface of this lake freezes, trapping
methane under it as strings of bubbles.
108 | ELEMENTS

32 50
Germanium Ge Tin Sn
After silicon, the semi-metal germanium is This metal is easy to purify from its ores,
the second most important semiconductor so humans have used it for more than
used in computer microchips. It is mostly 5,000 years. When mixed with copper, tin
found in ores of silver, lead, and copper. makes the alloys bronze and pewter; with
lead, it forms the alloy solder.

ATOMIC MASS 118.71

STATE Solid
Laboratory- DISCOVERY Around 3000 bce
refined disk Laboratory
of pure sample of
germanium pure tin
ATOMIC MASS 72.63
STATE Solid
DISCOVERY 1886 (Clemens Winkler)

114
Flerovium Fl
The name of this element was inspired
by the Russian scientist Georgy Flerov.
Flerovium was created for the first time
by making plutonium and calcium atoms
collide in a particle accelerator. Since
then, only a few more atoms have been
created. It is so radioactive that any
atoms that are made last only for a few
seconds before breaking apart.

ATOMIC MASS (289)

STATE Solid
DISCOVERY 1998 (team led by Yuri
Oganessian and Vladimir Utyonkov)
 CARBON GROUP | 109

FOCUS ON… ▶ High-quality

LEAD crystal glasses
sparkle in the
Easy to purify and
simple to shape, ▲ Lead does not ▲ The green glaze on light because
lead has been in rust, so sheets of this this ancient ceramic lead oxide
use for 9,000 years. metal are used to model of a pigsty comes is added to
waterproof roofs. from lead compounds. the glass.

82
Lead Pb
The symbol for this metal is taken from the Latin
word “plumbum,” from which the word “plumber”
also originates. This is because in ancient Roman
plumbing, lead was used to make water pipes.
Today, we know that pure lead is poisonous,
so it is seldom used for pipes. One
common use of lead is in
car batteries.

ATOMIC MASS 207.2

STATE Solid
DISCOVERY
Prehistoric

This ore is found

in the form of
long crystals.

Red crystals
of crocoite,
an ore of lead
H He

7
Li Be B C O F Ne
N
15
Na Mg Al Si S Cl Ar
P
33
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge Se Br Kr
As
51
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Te I Xe
Sb
La- 83
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Po At Rn
Lu Bi
Ac- 115
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Lv Ts Og
Lr Mc

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Nitrogen
Group
The atoms of nitrogen and other members of
this group form strong bonds. They release a
burst of energy when the bonds break, making
these elements useful in explosives and fuels,
such as the nitromethane fuel used to give a
power boost to this dragster.
112 | ELEMENTS

Nitrogen Group
Another name for the members of this group is the “pnictogens,”
which comes from the Greek word for “to choke.” This refers to
nitrogen’s tendency to cause choking in the absence of oxygen.
However, nitrogen, as well as phosphorus, are essential
ingredients in bones and muscles. This group includes
nonmetals, semi-metals, and metals.

Atmospheric nitrogen
The relatively unreactive nitrogen is the most Nitrogen 78%
abundant gas in Earth’s atmosphere. Every
living thing needs nitrogen compounds to
Oxygen 21%
grow, but most cannot use pure nitrogen.
Instead, bacteria in soil convert the gas into
usable compounds, which are collected
by plants via their roots. Animals take in Other gases 1%
nitrogen through food.
Gases in Earth’s atmosphere

Burning phosphorus
The most reactive member of the group is
phosphorus. Some forms of it will catch fire
on contact with air. A safer version is used in
matches, where phosphorus is mixed into the
rough strip on the box. When the match is
rubbed along here, the phosphorus heats up
and reacts with the match head, setting it alight.

Striking a
matchstick
 The arsenic in the
erupted material
will mix with the air.

Poisonous
element
All elements in this group
are deadly if used improperly,
but arsenic is so toxic that it is often
known as the “king of poisons.” Its
compounds have been used for many
centuries to kill rats and other pests.
Erupting volcanoes release large
amounts of poisonous arsenic gas
and dust, which dilutes in the air.

The Karymsky volcano,

in Kamchatka Peninsula,
Russia, has been erupting
since 1996
114 | ELEMENTS

Nitrogen
Earth's atmosphere is made up of about 78 percent
FOCUS ON… nitrogen, making this gas the most common pure
NITROGEN element on Earth. While it is relatively rare in solid
minerals, nitrogen is used by plants, fungi, and
Nitrogen is an important
ingredient in the chemical animals to make proteins.
industry. It is used in dyes,
explosives, and fertilizers. ATOMIC MASS 14.007
STATE Gas
DISCOVERY 1772 (Daniel Rutherford)

▲ Nitrogen compounds
called azo dyes can be used
to make many colors.

Pure nitrogen in
▶ Nitrogen-rich a glass sphere
compounds
are found in
explosives such
as dynamite. During
an explosion, the
nitrogen is released
as a burst of pure gas.

This mineral is
a mass of tiny
crystals that are
too small to see.
▲ Farmers add fertilizers
containing nitrogen to
soil to help crops grow
faster and taller.
NITROGEN GROUP | 115

7
N

Nitratine, a mineral
containing a
nitrogen compound
116 | ELEMENTS

15
Phosphorus P Arsenic
This element’s name means “giver of Almost every form of this semi-metal,
light” in Greek. There are different types pure or in compounds, is poisonous to
of phosphorus. Its white form is the living things. Because of this, arsenic
most reactive and catches fire as soon has long been used as a poison for
as it comes into contact with air. White controlling rats. It is also used as a
phosphorus is poisonous, and in certain component in microchips.
conditions, it glows in the dark.

ATOMIC MASS 30.974

STATE Solid
DISCOVERY 1669 (Hennig Brandt)
Purple crystals of
apatite, an ore
of phosphorus,
in rock
 NITROGEN GROUP | 117

33
As
ATOMIC MASS 74.922
STATE Solid Realgar is also
known as “ruby of Red crystals of
DISCOVERY Around 1250 (Albertus Magnus arsenic” because realgar, an ore
first purified the element) of its red color. of arsenic, in rock
118 | ELEMENTS

51
Antimony Sb
The symbol for this ATOMIC MASS 121.76
semi-metal comes from STATE Solid
“stibium,” the Roman word
for an ancient form of DISCOVERY Around 1600 bce
dark eye makeup (kohl),
which was made by
grinding up antimony
minerals into
a powder.

Laboratory-refined
crystals of
pure antimony
 NITROGEN GROUP | 119

FOCUS ON…
BISMUTH
Bismuth has a similar
▲ A soft bismuth alloy ▲ Adding bismuth ▲ Bismuth-based
weight and melting
inside sprinklers melts compounds to nail medicines are used to
point to lead but
during a fire, allowing polish gives it a soothe stomach aches
is a much safer,
the water to flow. soft pearly shine. and indigestion.
nontoxic alternative.

83
Bismuth Bi
Chemists have found that this silvery
metal is radioactive, but its atoms
disintegrate very slowly over millions of
years. Bismuth has a low melting point
and creates colorful crystals.

ATOMIC MASS 208.98

STATE Solid
DISCOVERY Around 1500

Crystals of bismuth
grown in a laboratory

115
Moscovium Mc
This element is produced by colliding ATOMIC MASS (289)
americium with calcium atoms. Only a few STATE Solid
atoms of it can be made at a time as they
all decay away into nihonium in a fraction DISCOVERY 2010 (team led by Yuri
of a second. Moscovium was first created Oganessian and Kenton Moody)
in 2010 in the Joint Institute for Nuclear
Research (JINR) in Dubna, Russia.
 H He

8
Li Be B C N O F Ne

16
Na Mg Al Si P S Cl Ar

34
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

52
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

La- 84
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Lu

Ac- 116
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Lr

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Oxygen
Group
Many life forms depend on oxygen for survival,
even in coral reefs under the sea—where fish, plants,
and tiny animals called corals take in oxygen mixed
into the water. Sulfur and selenium are also important
for life, but the other group members are not. In fact,
radioactive polonium is the deadliest element of all.
122 | ELEMENTS

Oxygen Group
Some scientists say this might be the first group in the periodic
table with no metallic members. There are three nonmetals: oxygen,
sulfur, and selenium. Tellurium and polonium are semi-metals,
although polonium is sometimes classified as a metal. No one yet
knows the nature of livermorium, an artificial element.

Combustion
The chemical reaction that
causes burning is called
combustion. Of the
elements in this group,
only oxygen plays a key
role in this process. It
occurs when pure oxygen
bonds to other elements,
releasing heat and light in the
process. Combustion usually
requires heat (to start it) and fuels,
which are substances that burn easily,
such as wood and oil.

Wood burns in a bonfire

Corrosion
Oxygen is highly reactive and forms
compounds known as oxides with other
elements. Similar to combustion but much
slower, corrosion is a reaction in which
oxygen in the air reacts with metals to create
oxides. The most common form of corrosion
is rust, which forms when iron reacts with
oxygen and water.

Chalcopyrite, a sulfide ore

of copper and iron

Ores
Natural substances containing useful
materials, such as metals, are known
as ores. Many important ores are
compounds with members of the oxygen
Pile of group, most often oxygen and sulfur.
rusted screws

Pure elements
Some members of this group are found pure in Deposits of pure sulfur in the
nature. While oxygen makes up one-fifth of the Danakil Depression, Ethiopia
air, solid sulfur is found in volcanic areas, where
the naturally hot conditions allow pure sulfur to
separate from its compounds.
124 | ELEMENTS

8
Oxygen O
As well as making up a
fifth of the air we breathe,
this gaseous element also
combines with metals and
other substances to make many of
the solid minerals of Earth’s rocks.
In addition, along with hydrogen,
oxygen forms all the water on Earth.
This is why oxygen is the most
common element on Earth’s surface.

ATOMIC MASS 15.999

STATE Gas
DISCOVERY 1771 (Carl Wilhelm
Scheele), 1774 (Joseph Priestley; his
finding was published first)

An average person
breathes in oxygen
up to 23,000
times in a day.

Liquid oxygen is made

by cooling the air to
-297.4°F (-183°C).

Liquid form of
pure oxygen
 OXYGEN GROUP | 125

FOCUS ON…
SULFUR
Sulfur has been in use
for centuries, from ▲ Sulfur is added ▲ Sulfur-rich compounds ▲ Car batteries use
keeping food fresh to to rubber in vehicle are added to dried fruits sulfuric acid to generate
making rubber stronger. tires in order to make and fresh food to stop electric currents.
them tougher. them going bad.

16
Sulfur S
This yellow nonmetal is found pure in
nature as well as in combination with
other elements in minerals. When sulfur
burns, it melts into a blood-red liquid
and produces a blue flame. It is also
called brimstone, which means
“burning stone.” Many ancient
cultures thought that sulfur was
the fuel that burned in the fires
of the underworld.

ATOMIC MASS 32.06

STATE Solid
DISCOVERY Prehistoric

Rectangular
crystals are
odorless
and brittle.

Yellow
crystals of
pure sulfur
Particles from the sun collide with
oxygen in Earth’s atmosphere to produce

green-colored
lights near the Poles
 POLAR LIGHTS
The sun emits “solar winds” of high-energy particles
that are pulled toward Earth’s North and South Poles
by the planet’s magnetic field. These particles collide
with the atoms of oxygen and other gases in the
atmosphere, producing light displays called auroras.
128 | ELEMENTS

34
Selenium Se
This semi-metal is named after Selene, ATOMIC MASS 78.971
the Greek goddess of the moon. It is STATE Solid
light-sensitive and so is used in solar
panels for making electricity and in DISCOVERY 1817 (Baron Jöns
light-sensors in laser printers and Jacob Berzelius)
photocopiers. It is also an ingredient
in antidandruff shampoos.
Gray selenium
has a hard, There are two forms
shiny surface. of pure selenium.
Gray selenium looks
metallic, while
the red form is a
crumbly powder.

Laboratory-refined
chunk of pure selenium
 52
Tellurium Te
While selenium is named for the
moon, the next member of the
group, tellurium, is named after
“tellus,” the Latin word for Earth.
It is used to make high-tech glass
such as the kind used in optical
fibers—a flexible cable with a
glass core, which is used to send
long-distance light signals.

ATOMIC MASS 127.6

STATE Solid
DISCOVERY 1783 (Franz-Joseph
Müller von Reichenstein)
Laboratory-refined
crystals of pure tellurium

84 116
Polonium Po Livermorium Lv
A rare and very dangerous metal, Although first made in the Joint Institute
polonium is a powerful source of for Nuclear Research (JINR) in the Russian
deadly radioactivity. It has city of Dubna, livermorium was named
been used in the triggers after Livermore, a town in California,
for atomic bombs. where many other superheavy elements
have been created. This element is made
ATOMIC MASS by fusing calcium and curium atoms. Its
(209) atoms exist for only a few thousandths
of a second before breaking apart.
STATE Solid
DISCOVERY ATOMIC MASS (293)
1898
(Marie Curie) STATE Solid
DISCOVERY 2000 (team led
by Yuri Oganessian, Vladimir
Utyonkov, and Kenton Moody)
Uraninite, an
ore of polonium
H He

9
Li Be B C N O F Ne

17
Na Mg Al Si P S Cl Ar

35
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

53
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

La- 85
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Lu

Ac- 117
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Lr

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Halogen
Group
The halogens are often found in the form of
compounds known as salts. The Dead Sea, a lake in
the Middle East, is a very salty water body because
of the halogen minerals dissolved in its warm
waters. The different salts of bromine, iodine, and
chlorine create bands of crystals in its shallows.
132 | ELEMENTS

Halogen Group
This group of elements is made up of highly reactive members,
which are called halogens. The word “halogen” means “salt former,”
alluding to how these elements react with metals to form salts.
The halogen group is mostly made up of nonmetals, with the
rare radioactive member astatine being classified as a semi-metal.

Forming salts
In chemistry, a salt is a stable chemical
compound made by an acid. Many
common salts in nature include one
of the halogens, often bonded
to metal atoms. The most
famous salt of all is sodium
chloride, a compound
of chlorine used in food.
Its mineral is called halite,
or simply “salt.”

Halite, the mineral

form of sodium chloride

Essential diet
Most of the halogens, which can be found in small
amounts in food, are very important for good
health. Chlorine and iodine especially have many
uses in the body’s chemical processes.
Compounds of fluorine are added to
toothpaste and water to keep teeth
strong. Astatine is the only
halogen not found in the body.
 HALOGEN GROUP | 133

Acids Cleaners
When bonded to hydrogen, the halogens The halogens are highly toxic and
form mostly strong acids. These can be used to kill germs. They are
compounds can react with present in detergents, bleaches,
many materials, even and other cleaning products. A
unreactive elements such small amount of chlorine is also
as gold. Mixing a halogen added to water to make it safe
acid and a metal produces for drinking, by killing germs
a salt and pure hydrogen gas. present that may cause
diseases. This practice has
saved millions of lives over
the last century.
Hydrochloric
acid is added Tap water treated
to zinc nuggets with chlorine

Kelp, found underwater,

is a source of iodine
134 | ELEMENTS

9
Fluorine F
The most reactive nonmetal of all, this pale
yellow gas can form compounds with almost
every element on the periodic table. Compounds
containing fluorine are used in toothpaste,
nonstick pans, and waterproof clothing.

ATOMIC MASS 18.998

STATE Gas
DISCOVERY 1886
(Henri Moissan)

Pure fluorine
gas can burn
its way through
almost anything,
including metals
and concrete.

Crystals of
fluorite, an
ore of fluorine
 HALOGEN GROUP | 135

▶ This
suitcase
is more
FOCUS ON… durable
CHLORINE because
it is made
In both its pure form
and in compounds, ▲ The bleach used ▲ Chlorine chemicals of a plastic
chlorine has plenty to make paper white are used to clean the containing
of uses. contains chlorine. water in swimming pools. chlorine.

17 35
Chlorine Cl Bromine Br
In its pure form, this halogen is a green This halogen is the only nonmetal
gas, although it is never found pure in that is liquid at room temperature.
nature. As it is very reactive, many chlorine The name bromine comes
compounds exist naturally, such as from the Greek
sodium chloride (common salt). word for “stench,”
because bromine
ATOMIC MASS 35.45
fumes have a
strong smell.
STATE Gas
DISCOVERY 1774 (Carl Wilhelm Scheele)

Clear crystals
of halite, an ore of Pure bromine
chlorine, in rock in a glass
sphere

Liquid bromine
is dark and
red-brown, while
bromine gas
is orange.

ATOMIC MASS 79.904

STATE Liquid
DISCOVERY 1826 (Antoine-Jérôme
Balard, Carl Löwig)
136 | ELEMENTS

53
Iodine I
This halogen was first discovered in
seaweed, and is an essential nutrient
in food. Iodine is also used in inks and
dyes, as an antiseptic for cuts, and for
purifying water. When heated, solid
iodine does not melt but instead
turns directly into a gas.

ATOMIC MASS 126.904

STATE Solid
DISCOVERY 1811
(Bernard Courtois)

Solid iodine
turning into gas

Glass sphere containing

pieces of pure iodine and
iodine vapor

117
Tennessine Ts
Discovered only in 2010, tennessine is ATOMIC MASS (294)
the newest member of the periodic table. STATE Solid
It is named after the state of Tennessee,
which is home to the Oak Ridge National DISCOVERY 2010 (teams from Joint
Laboratory—one of the first atomic Institute for Nuclear Research, Dubna,
research centers. Chemists think Russia; Lawrence Livermore National
tennessine might be a semi-metal, unlike Laboratory, California; and Oak Ridge
the other halogens. National Laboratory, Tennessee)
 HALOGEN GROUP | 137

85
Astatine At
Only tiny amounts of this radioactive
halogen exist in nature—around 1.05 oz Uraninite, an ore of
(30 g) in all of Earth’s rocks put together. uranium, contains a very
Astatine atoms are formed when francium small amount of astatine
and polonium atoms decay.

ATOMIC MASS (210)

STATE Solid
DISCOVERY 1940 (Dale
R. Corson, Kenneth Ross
MacKenzie, and
Emilio Segrè)
 2
H
He
10
Li Be B C N O F
Ne
18
Na Mg Al Si P S Cl
Ar
36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br
Kr
54
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I
Xe
La- 86
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At
Lu Rn
Ac- 118
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts
Lr Og

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Noble Gases
The colorful lights of a busy Hong Kong street are
glowing brightly thanks to the noble gases inside
them. “Neon” lights are shaped glass tubes filled
with neon and other gases. The elements in this
group glow brightly when an electric current is
passed through them.
140 | ELEMENTS

Noble Gases
The elements in the final group of the periodic table are the
noble gases. They are called “noble” because these gases
do not mix with ordinary elements. The noble gases are very
unreactive and their atoms only rarely form chemical bonds
with the atoms of other elements.

A new group
In the 1800s, chemists noticed that some reactions would leave
behind tiny amounts of unreactive gases. They realized that these
gases must be unknown unreactive elements. In 1894, the British
chemist Sir William Ramsay purified argon, discovering the first
noble gas, and soon found more.

Sir William Ramsay

Colorful plasma
Each element gives off light of a unique
color when heated or electrified. In the
1860s, scientists studying the sun
found a pattern of lights that did not
correspond to any element known at
that time. They named this unknown
element helium, and its pattern was
one of the first clues to the existence
of noble gases. A mixture of noble
gases in a plasma ball will emit unique
streaks of light when electrified.

Plasma ball
 NOBLE GASES | 141

Lighter than air

Airships and balloons filled with
helium, a noble gas, are lighter
than the surrounding air, so they
float upward. Helium is the
second-lightest element after
hydrogen. However, unlike hydrogen,
which is highly flammable, helium is
safe to use, although expensive. Propeller-powered
helium blimp

Inert gases
Because noble gases are inert (do not react
chemically) they can be used to protect other
elements from unwanted reactions. For example,
welders use a flow of argon to stop oxygen
in the air from getting to the hot metal.
Similarly, precious books and
documents are stored in pure
argon so no germs or mold
can damage them.

Metal welder
142 | ELEMENTS

FOCUS ON…
HELIUM
Helium has a very
low boiling point so ▲ Weather balloons filled ▲ Liquid helium is used to maintain the low
its liquid form is used with helium are sent high temperatures required by the superconducting
to keep high-tech into the atmosphere to magnets that make a maglev train (shown here
devices cold. collect data. in Shanghai, China) float above the tracks.

2
Helium He
This noble gas is much more common in space than
on Earth. It is produced from the radioactive decay
of uranium and thorium deep underground.
Helium collects in reservoirs of natural gas,
from where it is extracted.

ATOMIC MASS 4.003

STATE Gas
DISCOVERY 1895 (Per
Teodor Cleve, Nils Abraham
Langlet, and Sir
William Ramsay)

Helium makes up
about 10 percent of
Jupiter’s atmosphere

Jupiter, the
largest planet
in the solar system
 NOBLE GASES | 143

10
Neon Ne
The name of this gas means the “new
one.” Tiny amounts of the element are
released in volcanic eruptions and end
up in the air. Neon makes up around
one thousandth of 1 percent of
the atmosphere.

ATOMIC MASS 20.18

STATE Gas
DISCOVERY 1898 (Sir William Ramsay
and Morris Travers)

Pure neon
in a glass sphere

18
Argon Ar
About 1 percent of Earth’s atmosphere is made up
of argon, the most common noble gas on Earth.
Argon means the “lazy one” because early
chemists were left with it after removing
all other gases from air, and they found
it did not do anything at all.

ATOMIC MASS 39.95

STATE Gas
DISCOVERY 1894 (Lord Rayleigh and
Sir William Ramsay)

Small amounts of argon gas glow

pale purple when electrified.

Pure argon in
a glass sphere
144 | ELEMENTS

▼ Unlike rockets that use a chemical

reaction, the Dawn space probe is
powered by a jet of electrified
xenon gas created with
FOCUS ON… a strong electric
current.
XENON ◀ Small amounts of
xenon gas emit a
Xenon has several
specialist uses—as an blue-white light that
anesthetic, in bright is used in powerful
light bulbs, and even lamps and headlights.
as spacecraft fuel.

36 54
Krypton Kr Xenon Xe
This element’s name comes from the
Greek word “kryptos,” which means the
“hidden one.” Krypton is naturally present
in the air, but it is 20 times less abundant
than neon. It is primarily used in lasers
and in flash bulbs for
high-speed photography.

ATOMIC MASS 83.798

STATE Gas
DISCOVERY 1898 (Sir
William Ramsay and
Morris Travers) Pure xenon in a glass sphere

A balloon filled with xenon does not float,

This light is but drops straight to the ground. This is
given off by because this gas is five times heavier
krypton gas
when it is than air. Xenon is mixed with air in the
electrified. atmosphere, but out of every 10 million
atoms in the air, only one is xenon.

Pure krypton in ATOMIC MASS 131.293

a glass sphere STATE Gas
DISCOVERY 1898 (Sir William
Ramsay and Morris Travers)
 NOBLE GASES | 145

86
Radon Rn
Highly radioactive radon is created
as the thorium and uranium atoms
in rocks naturally break down.
Radon can gather in caves and
basements in certain areas, and
its radiation poses a risk to health.

ATOMIC MASS (222)

STATE Gas
DISCOVERY 1900 (Friedrich
Ernst Dorn)

Glass sphere containing

radon, air, and thorium

The radon in this sphere is

released from a tiny piece
of decaying thorium.

118
Oganesson Og
The final member of the periodic table ATOMIC MASS (294)
is oganesson. Its atoms have the highest STATE Solid
number of protons, electrons, and
neutrons of any element discovered DISCOVERY 2006 (teams from Joint
so far. This artificial element is named Institute for Nuclear Research, Dubna,
after the Russian nuclear physicist Yuri Russia and Lawrence Livermore National
Oganessian, who has been involved in Laboratory, California)
the discovery of 12 elements.
146 | ELEMENTS

Fascinating facts
IN NUMBERS BREAKING THE BANK
• The largest stable nucleus belongs • The Large Hadron Collider, the
to lead—it has 208 subatomic world’s largest particle accelerator,
particles (126 neutrons and has around $120 million worth
82 protons). of wire, made from the metals
The aluminum foil niobium and titanium, in it.
• Bismuth is very slightly
radioactive. It would take used in kitchens
is 0.00063 in • In the 1850s, aluminum
20 million trillion years for
(16 millionths of a meter) was twice as expensive
half of its atoms to decay.
thick. as gold—it was even used to
At less than 14 billion years
make dinner plates for royalty.
of age, even the universe is
not that old!
• Palladium is the most
• Buckminsterfullerene is one of the expensive precious metal. It costs
allotropes (physical forms) of carbon. almost 100 times as much as the
One molecule of it is made of 60 atoms same quantity of silver.
of carbon arranged in a ball.
• The body of an average adult human
contains 94.79 lb (43 kg) of oxygen and WEIRD BUT TRUE
0.0000071 oz (0.2 mg) of gold.
• Mercury is a liquid that is 13.5 times
• Around 1.2 billion tons (1.1 billion metric
denser than water. A person could sit on
tons) of iron are produced annually—
top of a pool of mercury without sinking.
enough to make a cube with sides about
2,362 ft (720 m) long, which is more than
• Recycling aluminum uses just 5
twice the height of the Eiffel Tower in
percent of the energy needed to
Paris, France.
extract pure uranium from its ores.
• Neutron stars are made only of neutrons
and not atoms. Astronomers have given • Lightning strikes occur nearly 50
this material the nickname neutronium. percent more often above nuclear power
One teaspoon of it would weigh around plants because the reactors release
100 million tons (90,718,000 metric tons)! charged krypton gas.
 FASCINATING FACTS | 147

DISCOVERERS • Sir J. J. Thomson, a British physicist,

discovered the first subatomic particles
• The Greek philosopher Democritus, in 1897. They are now called electrons.
in the 5th century bce, set out the idea
that everything is made from tiny units • In 1911, the New Zealand physicist
called atoms. Baron Ernest Rutherford led a team
that discovered the positively charged core
• In the early 1800s, the British chemist John of an atom, which he named the nucleus.
Dalton offered proof that atoms existed by He later showed that the positive charge
showing that gases always spread out evenly. was due to a subatomic particle called
the proton.
• In 1895, the French physicist Antoine
Henri Becquerel discovered that certain • In 1913, the Danish physicist Niels
materials gave out invisible rays. This was Bohr figured out how electrons and
named as radioactivity in the early 1900s protons were organized in an atom.
by the French physicists Marie and This helped scientists understand
Pierre Curie. how atoms could form bonds.

IN POPULAR CULTURE • In Middle-earth, the fictional world

created by the British author J. R. R.
• In the film Avatar, human miners are Tolkien, mithril is a metal that shines like
destroying the alien moon Pandora to extract silver and is stronger than steel. Once
a fictional element called unobtanium mined by dwarves, this metal
that is crucial to Earth’s survival. is priceless because it is no
longer produced. The most
• In Marvel comics and films, The element lead famous item made of mithril
vibranium is a very strong blocks the X-ray vision in Tolkien’s works is the
metal found only in the fictional of Superman, the mail armor worn by Frodo
African country of Wakanda. famous superhero Baggins, a hobbit.
This metal is used to make of DC comics
Captain America’s almost and films. • In Star Trek, a crystalline
indestructible shield. element called dilithium is
the central component of a
• Adamantium is a tough fictional alloy Federation spaceship’s warp drive
used in the claws of Wolverine, one of that allows it to travel many times faster
the X-Men in Marvel comics and films. than the speed of light.
148 | ELEMENTS

What’s in a name?
FROM MYTHOLOGY • Titanium is a strong, silvery metal, and
was named after the Titans, a group of
• Since it was first discovered not on powerful deities who battled the Olympian
Earth but in the sun, helium was named gods in ancient Greek mythology.
after the ancient Greek sun god Helios.
• The metal tantalum was named after
• The highly radioactive metal promethium the mythical figure Tantalus, who was
is named after Prometheus, the ancient punished by the ancient Greek gods by
Greek hero who stole fire from the gods. being put in a pool of water that he was
never able to drink from.
• The precious metal palladium was
named after the asteroid Pallas, which • Because of its similarity to tantalum,
itself was named after the ancient Greek niobium was named after Niobe,
goddess Pallas Athena. the daughter of Tantalus in ancient
Greek mythology.
• Because it produces many colorful
chemicals, the metal iridium was • Vanadium is a corrosion-resistant metal
named after Iris, the ancient Greek named after the Scandinavian goddess
goddess of rainbows. Freyja, whose Norse name is Vanadis.

REFLECTING COLORS • Rubidium gets its name from the Latin

word “rubidus,” meaning “deepest red,”
• Chlorine was named after the Greek word referring to the metal’s flames when burned.
“chloros,” meaning “greenish yellow,” to
describe the color of the pure gas. • The metal chromium was named after
the Greek word “chroma,” which means
• Cesium’s name comes from the Latin “color.” Its compounds have many
word “caesius,” meaning “sky-blue”—the different shades.
metal produces blue flames when it burns.
• The mineral orpiment, which is the main
• The element indium was named after the ore of arsenic, is yellow in color. The
color indigo. The metal’s atoms give off a element gets its name from the Greek word
dark-blue light when they are electrified. “arsenikon,” meaning “yellow orpiment.”
 WHAT’S IN A NAME? | 149

TEMPORARY NAMES FROM PLACES

• Scientists often need to refer to • Polonium is named after Poland.
elements that have not yet been
discovered. These elements are given • Gallium is named after “Gallia,” the
temporary names by an organization Latin name for France.
called IUPAC (The International Union of
Pure and Applied Chemistry). Even after • Lutetium is derived from “Lutetia,”
these elements are discovered, their the Roman name for Paris.
names and symbols must be approved
by IUPAC before they are accepted by
scientists throughout the world. UNUSUAL SYMBOLS
• Three-letter symbols, corresponding • Sodium’s symbol (Na) comes from its
to their temporary names, are assigned Latin name “natrium.” The word is itself
to elements before they are given official derived from the Arabic word “natrun,”
names. Hassium’s temporary name was meaning “headache”—sodium carbonate
unniloctium, with the symbol “Uno.” was an ancient remedy for a sore head.

• Until it was named in 2004, • The symbols for iron (Fe) and copper
Roentgenium was known as (Cu) come from the Latin words for these
unununium, and its symbol was metals, “ferrum” and “cuprum.” The
“Uuu.” Unununium corresponds to symbols for silver (Ag) and gold (Au)
the element’s atomic number 111. are also based on their Latin names,
“argentum” and “aurum.”
• Before they were officially named,
flerovium and livermorium were called • Tungsten’s symbol is W because
ununquadium and ununhexium, Latin it is called “Wolfram” in German,
words for their respective atomic which means “wolf soot.”
numbers 114 and 116.
• Tin’s symbol (Sn) is an abbreviation
• When element 119 is discovered of its Latin name “stannum.”
in the future, it will be first known as
ununennium, with the symbol “Uue.” • Potassium’s symbol (K) comes
Element 120 will be unbinilium, with from the Latin word “kalium,” which
the symbol “Ubn.” means “ash.”
150 | ELEMENTS

Glossary Brittle The property of

a hard, inflexible solid
that makes it break
Electron A negatively
charged particle moving
in a shell around the
Acid A reactive Antiseptic A substance into pieces when hit. nucleus of an atom.
chemical that that kills different
contains hydrogen. disease-causing germs. Bronze An alloy of Electron shell One of
copper and tin. the layers surrounding
Acidic Having the Artificial element An an atom’s nucleus that
properties of an acid. element produced in Cellulose A substance contains electrons.
a laboratory. containing carbon that
Alkali A chemical that is found in all plants, Element A substance
reacts easily with Atmosphere Layers especially in wood. that cannot be broken
acids and water. of gases around a body down any further into
in space. Chemistry The simpler ingredients.
Alkaline Having scientific study of
the properties of Atom The smallest the properties and Evaporation The
an alkali. unit of an element reactions of elements. process in which a
that contains protons, liquid turns to gas at
Allotrope A physical neutrons, and electrons. Combustion A reaction a temperature below
form of an element involving oxygen that its boiling point.
where the atoms are Atomic mass The total produces fire and heat.
arranged differently. number of protons and Extraction The
neutrons in an atom of Compound A process of separating
Alloy A substance an element. substance made of a substance from
made by mixing two the atoms of two or its source.
or more elements Atomic number The more elements.
together, of which at number of protons in Fossils The remains
least one is a metal. an atom of an element. Conductor A substance of ancient life forms
that lets electricity and found in rocks.
Alpha particle A Beta particle An heat pass through it.
cluster of two protons electron given off by an Fuel cell A device
and two neutrons atom during radioactivity. Corrosion A reaction that generates
emitted by some that attacks a solid electricity using a
radioactive elements. Boiling point The object, mostly made chemical reaction.
temperature at which a of a metal, and
Ammonite A type liquid turns into a gas. weakens it. Fuel rod A supply of
of shellfish that nuclear fuel used to
died out millions Bond The attraction Decay The process make electricity in a
of years ago. between atoms that of radioactive atoms nuclear reactor.
holds them together breaking apart.
Anesthetic A in an element or Gamma ray A
substance given a compound. Electrolysis A process very high-energy
to patients to that uses electricity to form of radiation
stop them from Brass An alloy of split a compound into released from
feeling pain. copper and zinc. its elements. radioactive atoms.
 GLOSSARY | 151

Halogen Means “salt electricity through neon Oxide A compound spacecraft that orbits
former.” A reactive mixed with other gases made of oxygen and Earth or another body
element that forms salts in a glass tube. another element. in space.
on reacting with metals.
Neutron A particle with Particle accelerator Semiconductor
Isotope A form of an no electric charge, A machine that makes A substance that
element where the found in the nucleus atoms or subatomic can either conduct
atoms have a different of an atom. particles travel at high electricity or block it.
number of neutrons. speeds so they can be
Noble gas A gas that collided with a target, Semi-metal A
Melting point The does not react with any or be smashed together. substance with
temperature at which a other element. A cyclotron is a type of features of both metals
solid turns into a liquid. particle accelerator. and nonmetals.
Nonmetal A solid,
Metal A type of liquid, or gaseous Physicist A scientist Smelting A process
element that is often element that is not a who studies physics— used to extract metals
a hard, shiny solid. metal or semi-metal. the field of science from their ores.
concerned with motion,
Microchip A piece of Nuclear fission A energy, and forces. Subatomic particle
silicon with electronic process in which an A particle that is
computer circuits. atom’s nucleus splits Proton A positively smaller than an atom.
in two, releasing a charged particle in the Protons, electrons,
Microscope A device huge amount of energy. nucleus of an atom. and neutrons are
used to see objects subatomic particles.
that are too small to Nuclear reaction A Radioactivity The
be seen by the eye. reaction that involves process in which Superheavy element
the atomic nucleus of an atom breaks apart, An artificial element
Mineral A naturally an element. releasing particles that has a very high
forming solid substance. and energy. number of protons.
Nuclear reactor A
Mixture The result machine in which Room temperature Supernova An
of two or more controlled nuclear 68°F (20°C). explosion that occurs
substances physically reactions take place. when a giant star dies.
mixed together. Rust A type of corrosion
Nucleus The core produced when iron Turbine A machine
Molecule A collection of an atom that reacts with water and that converts a flow
of atoms joined contains the protons oxygen in the air. of gas or liquid into
together by sharing and neutrons. rotational motion.
their electrons. Salt A chemical formed
Ore A mineral that when an acid reacts Ultraviolet An
Nebula A cloud of gas contains a useful with a metal, an alkali, invisible form of light
and dust in space. element such as a metal. or a similar substance. emitted by the sun.

Neon light A colored Organism The scientific Satellite A body X-ray An invisible
lamp made by passing term for a life form. like the moon or a form of radiation.
152 | ELEMENTS

Index
AB beryllium 32, 34
beta particles 11
cerium 73
chalcopyrite 123
acids 133
bismuth 6, 119 charcoal 11
actinides 14, 80–91
in creation of other elements chlorine 6, 25, 131, 132–133, 135
actinium 28, 82, 84–85
66, 67, 90, 99 chromium 45, 66
air (classical element) 4
bleach 133, 135 cinnabar 64
see also Earth’s atmosphere
Bohr, Niels 66 classical elements 4
albite 42–43
bohrium 66 cleaning products 133
alkali metals 20–29
boiling points 32, 40, 59, 142 cobalt 47, 50
alkaline earth metals (alkalis)
borax 94 cobaltocalcite 47
22, 30–37
boron 5, 74, 94, 95, 96 combustion 122, 123
allanite 73 boron group 92–99 compounds 4, 7, 8, 10, 12
allotropes 11 brass 39, 40 alkali metals 22–23, 25
alloys 98, 103, 108, 119 brimstone 125 alkaline earth metals 32,
from lanthanides 72, 73, 76 bromine 131, 135 34, 35
from transition metals 40, bronze 51, 103, 108 boron group 94, 95, 96
42, 50, 51, 53, 59 brookite 42–43 carbon group 102, 103,
alpha particles 11, 84 buckminsterfullerene 11 105, 109
Altamira Caves, Spain 48–49 halogen group 132, 133,
aluminum 42, 46, 95, 97 134, 135
americium 88, 119
ammonites 30–31
C lanthanides 72, 74, 79
cadmium 57 nitrogen group 112, 113,
antimony 118 cesium 22, 28 115, 116, 119
apatite 116 calcite 35 oxygen group 123, 125
argon 90, 140, 141, 143 calcium 31, 32, 35 transition metals 41, 45, 47,
arsenic 113, 116–117 in creation of other elements 51, 52, 54, 58, 59
astatine 55, 132, 137 108, 119, 129 conductors 40, 95, 96, 142
atomic mass 10, 13 California 83, 88, 89 see also semiconductors
atomic numbers 8, 13, 14, 15 californium 89 copernicium 67
atoms 4, 5, 8–9 carbon 11, 96, 102–103, Copernicus, Nicolaus 67
auroras 126–127 104, 107 copper 7, 40, 51, 108, 123
autunite 84–85 in creation of other elements production of bronze 103
azo dyes 114 58, 91 production of nickel 50
Badlands 59 carbon group 100–109 corrosion 50, 123
barium 37 carborundum 105 Crab Nebula 4
Becquerel, Henri 86 Carina Nebula 18–19 crocoite 109
benitoite 37 cave paintings 48–49 Curie, Marie 88–89
Berkeley, CA 83, 88 celestine 36 Curie, Pierre 89
berkelium 88 cellulose 103 curium 89, 91, 129
 INDEX | 153

DEF Ghiorso, Albert 90

glass 100–101
kernite 96
kohl 118
Danakil Depression, Ethiopia 123
darmstadtium 67 gold 5, 6, 40, 61, 62–63 krypton 144
Dead Sea 131 graphite 11, 103 Lake Baikal, Russia 106–107
deuterium 10 greenockite 57 Lake Natron, Tanzania 26–27
diamond 11, 104 groups (periodic table) 15 lanthanides 14, 68–79
Döbereiner, Johann 12 gypsum 35 lanthanum 68–69, 72
dubnium 65 hafnium 57 Lavoisier, Antoine 12
dysprosium 77 halite 132, 135 Lawrence, Ernest 91
earth, classical element 4 halogen group 130–137 Lawrence Berkeley National
“earths” 31, 32, 70 hard metals 40 Laboratory, CA 83
Earth’s atmosphere 5, 112, 127 hassium 66 lawrencium 91
Einstein, Albert 89 helium 18, 88, 140, 141, 142 lead 53, 67, 108, 109, 119
einsteinium 89 holmium 77 lepidolite 24
electron shells 9 human body 5, 102, 112, leucite 28
electrons 5, 8, 9 132 light-emitting diodes (LEDs) 71
erbium 70, 79 hydrochloric acid 133 liquids 6
europium 71, 74–75 hydrogen 8, 10, 16–19, 124, lithium 8, 12, 22, 24
ferberite 58 141 Livermore, CA 129
fermium 90 and calcium 35 livermorium 122, 129
fire 4, 112, 122 and halogens 132 living organisms 102, 121
fission 11, 66 and methane 107 see also human body
flames 22, 33 bomb (H-bomb) 89, 90 lutetium 79
Flerov, Georgy 108 indium 95, 99
flerovium 108 inert gases 141
fluorine 132, 134 insulators 95, 103 M
fluorite 134 iodine 131, 132–133, 136 magnesite 32
francium 28–29, 137 iridium 59 magnesium 32, 33, 34
iron 41, 46 magnetic elements
and corrosion 123 lanthanides 71, 74, 76
GHI in alloys 34, 44 transition metals 47, 50, 53
Gadolin, Johann 75 in compounds 48–49 malachite 7
gadolinite 70, 75, 77 in magnets 50, 71, 74 manganese 45
gadolinium 75 isotopes 10, 11, 87 matter see gases; liquids; solids
galena 53 Meitner, Lise 66
galinstan 98 meitnerium 66
gallium 98 JKL melting points 32, 94, 98, 119
gamma rays 11 jewelry 40, 54, 56, 61 of transition metals 40,
garnierite 50 Joint Institute for Nuclear 58, 60
gases 6, 112, 138–145 Research (JINR), Russia 65, Mendeleev, Dmitri 13, 90
see also nonmetals 119, 129 mendelevium 90
germanium 103, 108 Karymsky volcano, Russia 113 mercury 6, 12, 64, 76
154 | ELEMENTS

metals 5 nickel 50 oxides 32, 41, 48–49

see also boron group; nihonium 94, 99, 119 oxygen 6, 8, 10, 12, 124
carbon group; lanthanides; niobium 53 and nitrogen 112
polonium nitratine 114–115 in compounds 105
alkali metals 20–29 nitrogen 111, 112, 114–115 reaction with other elements
alkaline earth metals (alkalis) nitrogen group 110–119 22, 33, 77, 122, 123, 126–127
22, 30–37 nitromethane 111 oxygen group 120–129
hard metals 40 Nobel, Alfred 91
precious metals 40, 54, nobelium 91
56, 61 noble gases 138–145 PQR
soft metals 32, 95, 99 nonmetals 5, 12, 102, 125, 134, palladium 40, 54, 56
transition metals 38–67 135 particle accelerators 53, 83, 88,
meteorites 59 see also semi-metals 90, 91, 108
methane 106–107 Northern Lights 126–127 particles 127
Meydan Bridge, UAE 71 nuclear power 11, 80–81, 86 periodic table 13, 14–15
microlite 58 reactors 75, 83, 86, 87 phosphorus 5, 112, 116
millerite 55 nuclear reactions 8 plants 102
minerals 7, 21, 70, 105, 132 nucleus 9, 11 plasma 140
of alkaline earth metals 31, Oak Ridge National Laboratory, platinum 40, 60, 67
32, 35, 36 TN 136 Pluto 87
of boron group 95, 97 ocher 49 plutonium 87
of nitrogen group Oganessian, Yuri 145 pnictogens see nitrogen group
114–115, 118 oganesson 145 poisonous elements 37, 109,
of oxygen group 124, 125 opal 105 113, 116–117
of transition metals 42–43, ores 6, 7 transition metals 47, 54, 55, 64
50, 52, 55, 56, 57 of actinides 83, 84–85, polonium 121, 122, 129, 137
misch metal 72 86, 87 potassium 12, 20–21, 22,
modern elements 4 of alkali metals 24, 28–29 23, 25
molecules 10 of alkaline earth metals 35, praseodymium 73
molybdenite 53 36, 37 precious metals 40, 54, 56, 61
molybdenum 53 of boron group 95, 96, promethium 74
monazite 70, 73 97, 99 protactinium 85
moscovium 119 of carbon group 109 protons 5, 8, 9
Moseley, Henry 13 of halogen group 134, pure elements 6, 114, 123
135, 137 quartz 6, 56
of lanthanides 70, 73, 77 radioactivity 11, 28, 37, 99, 108,
NO of nitrogen group 116–117 119, 129, 137
neodymium 74 of oxygen group 123, 129 in actinides 81, 82, 84, 85, 86,
neon 65, 138–139, 143, 144 of transition metals 39, 42–43, 88, 89, 91
Neptune 86 44, 45, 47, 50, 53, 55, 57, in lanthanides 74, 78
neptunium 86 58, 64 in noble gases 142, 145
neutrons 5, 8, 9 osmium 59 in transition metals 54, 65, 67
 INDEX | 155

radium 37, 89 sodium 12, 22, 25, 26–27, University of California,

radon 84, 145 94 Berkeley 88
Rainbow Mountains, China 41 sodium chloride 23, 25, uraninite, ore
Ramsay, Sir William 140 132, 135 of actinides 86, 87
rare earth metals see lanthanides soft metals 32, 95, 99 of francium 28–29
realgar 116–117 solids 6 of polonium 129
rhenium 59 spacesuits 62–63 of radium 37
rhodium 55 sphalerite 99 of uranium 137
rhodonite 45 stars 4, 18–19 uranium 11, 86, 142, 145
roentgenium 67 steel 40, 44, 45, 47, 79 see also uraninite, ore
Röntgen, Wilhelm Conrad 67 stibium 118 and actinides 81, 82–83, 84,
rubber 125 Stockholm, Sweden 77 85, 87
rubidium 28 strontium 36–37 and nuclear fission 66
rusting 45, 123 subatomic particles 5, 8 and radium 37
ruthenium 54 sulfur 6, 12, 122, 123, 125 Uranus 83
Rutherford, Ernest 65 reaction with silver 56 vanadinite 44
rutherfordium 65 Super Heavy Ion Linear vanadium 44–45
Accelerator 83 variscite 97
supernova 4 volcanic activity 26, 113,
S Sydney Harbour Bridge, 123, 143
Salinas de Janubio, Spain Australia 33
23 symbols (periodic table) 15
salts 23, 26–27, 131, 132 WXYZ
samarium 71, 75 water 4, 10, 103
scandium 42 TUV and alkaline earth metals
Seaborg, Glenn T. 65 tantalum 58 30, 32
seaborgium 65 technetium 54 and alkalis 22, 23, 24
selenium 121, 122, 128, 129 tellurium 122, 129 and boron 94
semiconductors 103, 108 Tennessee 136 and halogens 132, 133,
semi-metals 5, 136 tennessine 136 135, 136
in boron group 94, 96 terbium 70, 71, 76 and lanthanides 77
in carbon group 102, thallium 93, 99 and oxygen 121, 123, 124
105, 108 Thor 85 welding 141
in nitrogen group 112, thorianite 85 xenon 144
116, 118 thorium 82–83, 85, 142, 145 ytterbium 70, 79
in oxygen group 122, 128 thulium 78 Ytterby, Sweden 70
silicon 45, 46, 101, 103, 105 tin 103, 108 yttrium 52, 70
silver 40, 47, 56, 108 titanium 40, 42–43 Zhangye Danxia Landform
slime 94 torbernite 85 Geological Park, China 41
smelting 39 transition metals 38–67 zinc 51, 57, 67, 99, 133
Society for Heavy Ion tritium 10 zirconium 52, 57
Research, Germany 67 tungsten 58
156 | ELEMENTS

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Museum 109ca (Tomb), Oxford Popova 95b, Rui Matos / Rolmat 73cra,
University Museum of Natural History Abdul Sami Haqqani / Shadow69
61bc, 123cra, RGB Research Limited 141cra, Daniel Poloha / Spiderment
5cl, 5c, 5cr, 6cra, 6cl, 6cr, 12c, 12crb, 132–133, Studio306 119ca, Bert
19cr, 22cl, 22cr, 22bl, 25bl, 25br, 28bl, Folsom / Treb999 119cra, Abel Tumik /
28–29, 32cr, 34cra, 34b, 35clb, Yamahavalerossi 114cla; Fotolia: apttone
36–37c, 37br, 42bl, 43cr, 44–45c, 11ca, efired 71tl, TimurD 114clb, Pavlo
45cra, 46, 47clb, 51cra, 51clb, 52cla, Vakhrushev 25cra; Getty Images: Hulton