1. When two atomic orbitals having same energy and proper symmetry are approaching each other molecular orbitals are formed by the linear combination of atomic orbitals.
2. The no. of molecular orbitals formed is equal to no. of atomic orbitals undergoing combination.
3. During LCAO , two types of molecular orbitals are formed, bonding and antibonding molecular orbitals.
4. Electrons are added to various molecular orbitals according to Aufbau‟s principle, Paul‟s exclusion principle and Hund‟s rule.