Question

(a) Distinguish between bonding and antibonding molecular orbital. 

(b) Write the molecular orbital electronic configuration of N₂ molecule. Calculate its bond order and predict its magnetic behaviour.

Answer 1

(a) bonding and antibonding molecular orbital:

Bonding molecular orbital	Antibonding molecular orbital
(i) Its energy is less than that of parent atomic orbitals.	Its energy is greater than that of parent orbitals orbitals.
(ii) It is more stable than the parent atomic Orbitals.	It is less stable than the parent atomic orbitals.
(iii) In bonding molecular orbitals, the probability of finding electrons is maximum	In anti-bonding molecular orbital, the probability of finding electrons is minimum
(iv) It contributes towards the shape of molecule.	It does not contribute towards the shape of molecule.

(b) Molecular orbital configuration of N₂:

(σ1s)²(σ*1s)²(σ2s)²,(σ*2s)²(π2p_x)² = (π2p_y)²,(σ2p_z)²

Bond order = \(\frac{1}{2}\)(\(N_b-N_a\))

= \(\frac{1}{2}\) (10 - 4) = 3

Magnetic behavior - Diamagnetic due to absence of unpaired electrons.