Question

Explain the postulates of Molecular Orbital Theory.

Answer 1

(i) In a moleucle, electrons are present in new orbitals called molecular orbitals.
(ii) Molecular orbitals are formed by combination of atomic orbitals of equal energies(in case of homonuclear molecules) or of comparable energies.(in case of heteronuclear molecules).
(iii) The number of molecular orbitals formed is equal to the number of atomic orbitals undergoing combination.
(iv) Two atomic orbitals can combine to form two molecular orbitals. Out of these two molecular orbitals one has a lower energy and the other has a higher energy. The molecular orbital with lower energy is called bonding molecular orbital and the other with higher energy is called anti bonding molecular orbital.
(v) The shapes of molecular orbitals depend upon the shapes of combining atomic orbitals.