Introduction to
Chemistry
Explore the fundamental building blocks of our world, from the pioneering
work of chemistry's founding fathers to the atoms, molecules, elements,
compounds, and mixtures that make up the universe around us.
FATHER OF CHEMISTRY : LAVASIOUR
Atom and Molecule
1. An atom is the smallest unit of matter that still retains the chemical
properties of an element. It consists of a nucleus surrounded by a cloud
of electrons.
2. A molecule is a group of two or more atoms held together by chemical
bonds. Molecules are the fundamental building blocks of all matter,
including living organisms.
3. Molecules can be made up of atoms of the same element (e.g., oxygen
molecule O₂) or atoms of different elements (e.g., water molecule H₂O).
Elements, the Periodic Table, Natural
Elements, and Synthetic Elements
The Periodic Table Natural Elements Synthetic Elements
The periodic table is a masterful Natural elements are those that Synthetic elements are those
organization of all known exist in nature and cannot be created in laboratories through
chemical elements, arranged by broken down into simpler complex nuclear processes,
their atomic number and substances, such as gold, silver, expanding the periodic table
chemical properties. and carbon. with new, often unstable
elements.
Compounds
Compounds are pure substances made up of two or more different elements
chemically bonded together. They have a fixed composition and unique
properties distinct from their individual components.
Examples of common compounds include water (H2O), table salt (NaCl), and
carbon dioxide (CO2). Compounds can be classified based on their chemical
structure, such as organic and inorganic compounds.
Mixture
A mixture is a combination of two or more substances that are not
chemically bonded. Unlike compounds, the components in a mixture retain
their individual properties and can be separated by physical means. Mixtures
can be homogeneous or heterogeneous, depending on the distribution of
the components.
Common examples of mixtures include sand and water, salt and pepper, and
air. Mixtures are essential in our daily lives, as they allow us to create a wide
range of useful materials, from alloys to foods.
Orbit & Sub Orbit
Orbital Shells 1
Atoms are structured with electrons
orbiting the nucleus in specific energy
levels called orbitals or shells. The 2 Suborbital Regions
innermost shell is the 1s orbital, Within each orbital shell, there are
followed by progressively higher energy smaller suborbital regions designated as
shells like 2s, 2p, 3s, 3p, etc. s, p, d, and f. These suborbitals have
distinct shapes and energy levels that
influence how electrons are distributed
Electron Configuration 3 around the nucleus.
The specific arrangement of electrons in
the various orbitals and suborbitals of
an atom is known as its electron
configuration. This configuration
determines the chemical properties and
behavior of the element.
Electron, Proton, and Neutron with
Discoverers
Electron Proton Neutron
The negatively charged The positively charged The electrically neutral
subatomic particle discovered by subatomic particle discovered by subatomic particle discovered by
J.J. Thomson in 1897. Electrons Ernest Rutherford in 1919. James Chadwick in 1932.
are found in all atoms and play a Protons are found in the nucleus Neutrons, along with protons,
crucial role in chemical reactions of all atoms and determine the make up the nucleus of an atom
and the formation of bonds. element's identity. and play a role in atomic
stability.
The Nucleus
Protons
1
Positively charged particles at the core of the atom.
Neutrons
2
Electrically neutral particles that stabilize the nucleus.
Nucleus
3 The collective term for protons and neutrons in
the nucleus.
The nucleus is the dense, central core of an atom, containing the protons and neutrons. It is the heart of the
atom, holding the positive charge and most of the atom's mass. The configuration and number of protons
and neutrons determines the identity and properties of the element.
Valence Electrons and Valency
Valence electrons are the outermost electrons in
an atom that participate in chemical reactions. The
number of valence electrons determines an atom's
valency, which is the combining capacity or
reactivity of an atom.
Valency is the number of bonds an atom can form
with other atoms to achieve a stable electron
configuration.
Element Atomic Number Symbol Valency Valence
Electrons
Hydrogen 1 H 1 1
Helium 2 He 0 2
Lithium 3 Li 1 2
Beryllium 4 Be 2 2
Boron 5 B 3 2
Carbon 6 C 4 2
Nitrogen 7 N 3 5
Oxygen 8 O 2 6
Fluorine 9 F 1 7
Neon 10 Ne 0 8
Sodium (Na) 11 Na 1 8
Magnesium (Mg) 12 Mg 2 8
Aluminium 13 Al 3 8
Silicon 14 Si 4 8
Phosphorus 15 P 3 5
Sulphur 16 S 2 6
Chlorine 17 Cl 1 7
Argon 18 Ar 0 8
Potassium (K) 19 K 1 8
Calcium 20 Ca 2 8
Scandium 21 Sc 3 9
Titanium 22 Ti 4 10
Vanadium 23 V 5, 4 11
Chromium 24 Cr 2 12
Manganese 25 Mn 7, 4, 2 13
Iron (Fe) 26 Fe 2, 3 14
Cobalt 27 Co 3, 2 15
Nickel 28 Ni 2 16
Copper (Cu) 29 Cu 2, 1 17
Zinc 30 Zn 2 18
Branches of Chemistry and Examples
in Daily Life
1 Organic Chemistry 2 Inorganic Chemistry
Focuses on the study of carbon-based Examines the properties and reactions of
compounds, such as those found in living materials not derived from living things, like
organisms, including medicines, fuels, and metals, minerals, and salts.
plastics.
3 Analytical Chemistry 4 Examples in Daily Life
Identifies and quantifies the chemical Chemistry is all around us - in the food we
components of substances, used in areas eat, the air we breathe, the detergents we
like forensics, environmental monitoring, use, and the medicines that keep us healthy.
and quality control.
