- p, q, r, t ; - q, r, s, t ; - p, q, r ; - p, q, r, s

Sol. B 2 σ 1s 2 σ *1s 2 σ 2s 2 σ *2s 2 π 2p x 1 = π 2p y 1 Bond order = = 1 Paramagnetic with two unpaired electrons.

It undergoes oxidation as well as reduction which can be explained by taking the following reactions.

2B + 3Cl 2 ⎯→ 2BCl 3 ; 2B + 3Ca ⎯→ Ca 3 B 2 (boride)

Mixing of 's' and 'p' orbitals takes place.

N 2 σ 1s

2 σ *1s 2 σ 2s 2 σ *2s 2 π 2p x 2 = π 2p y 2 σ 2p z 2

Bond order = = 3 Diamagnetic

It undergoes oxidation as well as reduction which can be explained by taking the following reactions.

N 2 + O 2 ⎯→ 2NO ; 6Li + N 2 ⎯→ 2Li 3 N

Mixing of 's' and 'p' orbitals takes place.

O 2 – σ 1s 2 σ *1s 2 σ 2s 2 σ *2s 2 σ 2p z 2 π 2p x 2 = π 2p x 2 π *2p x 2 = π *2p y 1

Bond order = = 1.5 Paramagnetic with one unpaired electron.

It undergoes oxidation as well as reduction which can be explained by taking the following reactions.

O 2 – ⎯→ O 2 + e – ; O 2 – + e – ⎯→ O 2 2–

Mixing of 's' and 'p' orbitals does not take place.

O 2 σ 1s 2 σ *1s 2 σ 2s 2 σ *2s 2 σ 2p z 2 π 2p x 2 = π 2p x 2 π *2p x 1 = π *2p y 1

Bond order = = 2 Paramagnetic with two unpaired electrons.

It undergoes oxidation as well as reduction which can be explained by taking the following reactions.

O 2 ⎯→ O 2 + + e – ; O 2 + e – ⎯→ O 2 –

Mixing of 's' and 'p' orbitals does not take place.