Atomic structure and stoichiometry. Isotopes of an element. Avogadro's number and the concept of a mole. The atomic weight scale and atomic mass unit. The significance of balanced chemical equations. The hydrogen atom and the polyelectronic atoms. Atomic orbitals from quantum theory. The electronic configurations of atoms. The building up of the periodic table. The nature of the chemical bond. Lewis structure. Valence shell electron pair repulsion theory. From the Lewis theory to the oxidation state of an element. Oxidation-reduction reactions. Inorganic nomenclature. Properties of the elements and their compounds. The law of chemical equilibrium. The theory of acids and bases.