According to MO theory which of the lists ranks the nitrogen species in terms of increasing bond order ?
- N22- < N2- < N2
- N2 < N22- < N2-
- N2- < N22- < N2
- N2- < N2 < N22-
Answer
(1) N22- < N2- < N2
Solution
Bond order = 12(Nb - Na)
N2 (14 e⁻): Nb = 10, Na = 4 ⇒ B.O. = 3
N2- (15 e⁻): extra electron in *2p ⇒ B.O. = 10 - 52 = 2.5
N22- (16 e⁻): ⇒ B.O. = 10 - 62 = 2
∴ Increasing bond order: N22- < N2- < N2
Answer: (1)