Carbon
Discovered: Known since ancient times. It was first recognized as an element in the second half
of the 18th century.
Name: A.L. Lavoisier proposed carbon in 1789 from the Latin carbo meaning "charcoal." A.G.
Werner and D.L.G. Harsten proposed graphite from the Greek grafo meaning "to write,"
referring to pencils, which were introduced in 1594. Diamond is a hybrid word from the
Greek meaning "transparent" and "invincible." The blue color of the Hope diamond arises
from a trace amount of boron substituting for carbon in the lattice. Likewise, trace
nitrogen accounts for the yellow color of the Tiffany diamond. In 1985 a new allotrope
of carbon buckminsterfullerene was created in the laboratory. It consists of 60 carbon
atoms in an arrangement similar to surface of a soccer ball. Its name derives from the
inventor of the geodesic dome whose same is very similar and it is found in interstellar
space. Other enclosed structures with differing numbers of carbon atoms also exist.
Occurrence: Widespread, but not particularly plentiful in nature. Major sources: elemental
forms, carbonates, CO2, living and dead organic matter. (The first two are most
important).
Isolation: Found naturally (both graphite and diamond); both can also be made artificially.
Cost for 1 gram, 1 mole: $0.04, $0.48 (graphite)
Natural Isotopes: 12C (98.89%) 13C (0.11%) 14C (trace)
Physical and Graphite Diamond
Chemical Very soft (Moh's < 1) Very hard (Moh's = 10)
Properties: Electrical conductor Electrical insulator
Black in color Colorless
Less dense form More dense form
More reactive form Less reactive form
Flaky texture
Reactions: burning: C + O2 CO2
C + ½ O2 CO
H2O(g) + C(s) CO(g) + H2 (g) (“water-gas shift” reaction)
Uses: Graphite: Solid lubricant Diamonds: Grinding/abrasives
Electrodes Adornment
Crucibles
Neutron moderator in nuclear reactors
High strength composites
(in tires, rackets, skis, etc.)
Chlorine
Discovered: By C.W. Scheele in 1774, but he thought it was a compound. Sir Humphrey Davy
demonstrated that Cl2 was an element in 1810.
Name: Proposed by Davy in 1811 it comes from the Greek chloros meaning "yellowish or light
green" referring to its color.
The word halogen was introduced in 1811 by J.S.C. Schweigger to describe the property
of chlorine to produce salts when directly reacted with metals. It comes from a hybrid of
Greek words meaning "to produce sea salt."
Occurrence: Moderate to low abundance, widespread in nature, and never found free. Most
chlorine is found in NaCl in either evaporated water pools or the ocean. MgCl2 and
CaCl2 are also found in substantial quantities.
Isolation: a) Electrolysis of aqueous NaCl (to Cl2, H2, and NaOH)
b) Electrolysis of molten NaCl (to Cl2 and Na)
Cost of 1 gram, 1 mole: 0.23, $8.24
Natural Isotopes: 35Cl (75.5%) 37Cl (24.5%)
Physical and Yellow-green gas with a sharp odor
Chemical Strong oxidant
Properties: Very electronegative
Very reactive
Dissolves in and reacts with water
Toxic
Reactions: Cl2 + H2 dark No reaction
h
Cl2 + H2 2 HCl
Cl2 + CO Cl2CO (phosgene, WW I poison gas)
Cl2 + H2O HCl + HClO (gives bleach when NaOH is present)
Cl2 reacts with aqueous CaCl2 at 0 ºC to form solid Cl2•7.3H2O
Cl2 + PhI cold PhI•Cl2 (a “solid form” of chlorine that is easily weighed)
Uses: Synthesis of chloro organic compounds
Paper bleaching
Disinfectants (e.g. of water supplies)
Synthesis of inorganic chlorides
Fluorine
Discovered: First isolated by H. Moissan in 1886 after 74 years of efforts by various investigators
(The unknown element had been observed as a constituent of minerals.)
Name: From the mineral fluorospar (CaF2), suggested in 1812 by A.-M. Ampere (almost 75 years
before it was isolated!). Fluorospar is derived from the Latin word fluor meaning "to flow."
Note: Fluorescence was first observed as the light emission from fluorospar in 1852.
Occurrence: Moderately abundant, never occurs as the free element. Most common minerals:
fluorite (CaF2), cryolite (Na3AlF6), and fluorapatite (Ca5(PO4)3F).
Isolation: Interestingly, the only practical method of preparing F2 is the one used to isolate it the
first time in 1886 (with safeguards to prevent the fire that happened then). Electrolysis
of KF in anhydrous HF (1:2) at 72 ºC. H2 is the by-product gas and must be kept
separated from the F2 to prevent explosions. The cells contain no flammable material
and have a protective fluoride coating for the same reason.
Cost of 1 gram, 1 mole: $1.05, $19.90
Natural Isotopes: 19F (100%)
Physical and Most electronegative element
Chemical Pale yellow gas that condenses to a canary yellow liquid
Properties: Corrosive
F-F bond energy is low
Most reactive of the elements
Finely divided metals, glass, ceramics, carbon, and water(!) spontaneously burn
in the presence of F2
Low melting point
Binary fluorides are unusually volatile (compared with the corresponding
halides or oxides)
Reactions: U + 3 F2 UF6 (used to separate U isotopes for nuclear power, accounts
for 70-80% of F2 use)
Cl2 + 3 F2 2 ClF3 (used as an incendiary by Germany in WWII)
F2 + organic compounds explosion and fire
Uses: Artificial blood (fully fluorinated long hydrocarbons stores large amounts of oxygen)
Etching glass (HF)
Hydrochlorofluorocarbons are used as refrigerants and as inert gases in the computer
industry. Originally, chlorofluorocarbons were used for this purpose, but have been
phased out of use because they damage the ozone layer. This is ironic as they were
originally used because they were completely non-toxic and unreactive towards
equipment.
Dental health. (Fluoride is added to most drinking water supplies and toothpastes. It
replaces a surface -OH group on the enamel making it less susceptible to acid attack.)
Nitrogen
Discovered: Independently by Daniel Rutherford and by C.W. Scheele and H. Cavendish in 1772.
Name: Proposed by J.-A.-C. Chaptal in 1790 from the realization that it was a component of HNO3
and nitrates (from the Greek niter and gen meaning "to form from salt peter") A.L. Lavoisier
suggested azote (meaning "no life" referring to its inability to support aerobic life, c.f.
azides, azo compounds, etc.). Likewise, the German term for nitrogen, Stickstoff, means "to
choke."
Occurrence: N2 is 75-78 volume %, mole %, and weight % of air. It is non-abundant in the crust,
however KNO3 and NaNO3 deposits are found in some arid regions of the world.
Isolation: Liquification and distillation of air (b.p. -196 ºC, 77 K)
Cost of 1 gram, 1 mole: $0.01, $0.24
Natural Isotopes: 14N (99.6%) 15N (0.4%)
Physical Properties: Odorless, colorless gas
Chemically inert
Very electronegative
Atomic N can be generated by passing an electrical discharge through a ca.
1 torr sample of N2. (In spite of the very favorable thermodynamics of
recombination, several minutes are required for complete reaction
because at low pressure this is a termolecular process.)
high P
Reactions: N2 + 3 H2 high T 2 NH3 (ammonia)
4 NH3 + 8 O2 4 HNO3 + 4 H2O
NH4NO3 2 H2O + N2O (laughing gas)
C3H5(OH)3 + 3 HNO3 catalyst 3 H2O + C3H5(NO3)3 (nitroglycerine)
Uses: NH3 is the largest volume chemical produced in the U.S. (by moles) (It is the starting
material for many N containing chemicals.)
Fertilizers (4 of the top 13 chemicals produced in the U.S. in 1980 contained N and were
connected to fertilizer synthesis.)
Explosives (1,3,5-trinitrotoluene, nitroglycerin, etc.)
Refrigerant (liquid N2)
Anesthetic (laughing gas)
Comprises about 15% of proteins by weight
Oxygen
Discovered: J. Priestly and C.W. Scheele (independently) in 1773-74.
Name: By A.L. Lavoisier in 1777. It is a hybrid word derived from the Greek oxys meaning "acid
former" from the belief that it was a constituent of all acids. "Ozone" is derived from the
Greek word ozein meaning "to smell."
Occurrence: Comprises about 20% of our atmosphere, 45% of the earth's crust, and 89% of water.
It is also by far and away the major component of bodies of water. There are 2
allotropes of oxygen: dioxygen (O2) and ozone (O3), both of which occur in nature.
Almost all of the O2 found in nature is of biological origin.
Isolation: Obtained by the fractional distillation of air. Ozone is formed by exposing dioxygen
to an electric discharge or to ultraviolet light. One can often smell ozone near electrical
equipment that produces sparks.
Cost of 1 gram, 1 mole: $0.07, $0.22
Natural Isotopes: 16O (99.8%) 17O (0.04%) 18O (0.2%)
Physical and Dioxygen Ozone
Chemical Paramagnetic Diamagnetic
Properties: Colorless, odorless gas Blue gas with a sharp odor
Safe to breathe Toxic ([O3] > 1 ppm for time > 10 min)
Very reactive (reacts with every Even more reactive
element except He, Ne, and Ar)
Strong oxidizer Very strong oxidizer
Fairly soluble in water and Bent Structure
organic solvents
Blue when liquefied
Reactions: Dioxygen: 2 HCCH + 5 O2 4 CO2 + 2 H2O
2 H2 + O2 2 H2O
Ozone: Ozone is an important component of the stratosphere where it absorbs
harmful UV radiation before it reaches the ground. This ozone layer may be
in danger because of the slow diffusion of chlorofluorocarbons (freons) into
the stratosphere. The reactions that are thought to occur there are shown
below.
CF3Cl h CF3 + Cl
Cl + O3 ClO + O2 (Note: This and the next reaction form a
ClO + O Cl + O2 repeating chain.)
Uses: Blast furnaces in steel making (atmosphere enrichment)
Industrial NH3, MeOH, and ethylene oxide syntheses
Rocket fuel (with H2), used in the space shuttle
Phosphorus
Discovered: By Hanning Brandt in 1669 (by putrefying urine, boiling it to a paste, then reductively
distilling it; think about this next you don't like a lab that's been assigned)
Name: From the Greek (fos and fero) meaning “light bearing” because it glows in the dark when
exposed to air. Brandt was the first person credited with naming an element. All previous
elements had been known since antiquity.
Occurrence: Moderate abundance, widespread distribution, but never found pure. There are over
200 P containing minerals, the apatites (Ca3(PO4)2•CaX2) being the most significant.
Isolation: 2 Ca3(PO4)2 + 6 SiO2 + 10 C P4 + 6 CaSiO3 + 10 CO
Cost of 1 gram, 1 mole: $0.21, $6.38 (red)
Natural Isotopes: 31P (100%)
Physical and At least 5 crystalline forms plus several amorphous forms are known (all
Chemical melt to the same liquid).
Properties:
White P4 - Most common form
Most reactive form
Crystalline
Waxy consistency
Slow oxidation of vapor emits
yellow-green light (phosphorescence)
Burns in air
Highly toxic (fatal dose ca. 50 mg)
Red P4 - Made by heating white P4 to ca. 300 ºC
Less reactive than white
Essentially non-toxic
Polymeric
Black P4 - Made by heating white P4 under pressure
Thermodynamically most stable form
Semi-conductor
Highly branched polymer
Reactions: P4 + O2 P4O6 or P4O10
P4O10 + 6 H2O 4 H3PO4
P4 + S P4S3 (matches that will strike anywhere)
Uses: Fertilizers (as phosphates)
Fine china (Ca3(PO4)2)
Detergents and water softeners (as phosphates)
Silicon
Discovered: J.J. Berzelius in 1824
Name: From the Latin silex for "flint." It ends in -on because of its resemblance to carbon.
Prehistoric weapons and tools were made with this silicon containing mineral.
Occurrence: It is the second most abundant element in the earth's crust, but only the seventh
most abundant in the universe. It never occurs free and is almost always combined
with oxygen. It is a component of many minerals: olivine (MII2SiO4), quartz
(SiO2), amethyst, flint, opal, agate, jasper, granite, asbestos, micas, feldspars, etc.
Isolation: SiO2 + 2 C Si + 2 CO
Cost for 1 gram, 1 mole: $0.79, $22.00
Natural Isotopes: 28Si (92.2%) 29Si (4.7%) 30Si (3.1%)
Physical and Semiconductor
Chemical Metalloid
Properties: Shiny blue-gray metallic luster
Low tendency towards catenation (doesn't form long chains with itself)
Multiple bonds are much weaker than for carbon analogues (because silicon
doesn't use its p-orbitals for -bonding)
Chemically inert (attacked by halogens, dilute alkali)
Very oxophilic
o
Reactions: Si + C 2000 C (SiC)x (carborundum)
Si + 2 Cl2 red heat SiCl4
Uses: Semi-conductors
Construction (SiO2, sand in cement)
Recreation (SiO2, sand on beach)
Glass (SiO2)
Abrasives (SiC)
Synthetic oils, rubbers, and greases (silicones)
Sulfur
Discovered: By cavemen. First proposed as an element by A.L. Lavoisier in 1777.
Name: From the Latin word sulphyrium, which is derived from the Sanskrit sulvere, meaning "the
enemy of copper." and is likely to be an alchemical term. It is called brimstone in the Bible,
which is a corruption of the German word for sulfur brennstein meaning "stone that burns."
It is a chalcogen which means "derived from copper (or bronze)" from the Greek.
Occurrence: Moderately abundant and widespread in nature, usually found in combined form.
Minerals: sulfates [gypsum (CaSO4•2H2O), barite (BaSO4), epsom salts (MgSO4)],
sulfides [pyrite (FeS2, cinnabar (HgS), galena (PbS), sphalerite (ZnS), chalcopyrite
(CuFeS2)]. Elemental sulfur. H2S is found in natural gas. Large deposits of
elemental sulfur are located along the Gulf Coast in Texas and Louisiana.
Isolation: Hot water and compressed air is forced in the caprock of salt domes melting the sulfur and
forcing it out. (The sulfur is probably the result of anaerobic bacteria consuming sulfate
deposits.) This sulfur is usually very pure (> 99%). Some sulfur is obtained as a result of
contamination of natural gas (CH4) by H2S (up to 30%).
Cost for 1 gram, 1 mole: $0.09, $2.87
Natural Isotopes: 32S (95.0%) 33S (0.8%) 34S (4.2%) 36S (0.01%)
Physical and Shows the greatest allotropy of any element
Chemical Has a strong tendency to catenate
Properties: Very reactive, particularly at higher temperatures
Combines directly with most elements
Most common allotrope is orthorhombic -cyclo S8
Good thermal and electrical insulator
Tasteless with little odor
Colors of some sulfur allotropes
S2 (g) - blue-violet S6 - orange-red
S3 (g) - cherry red S8 (s) - yellow
Reactions: S + O2 SO2 ("burning")
2 S + O2 2 SO3
SO3 + H2O H2SO4 (a source of acid rain)
Uses: Fungicides and insecticides
Vulcanizing rubber
A component of black (gun)powder
Almost 90% of sulfur is converted into H2SO4 (40 million tons/year world wide)
Most uses of sulfur make use of sulfuric acid as a starting material
Fertilizer (ca. 50% of the H2SO4)
Synthetic fabrics
Paper production
