Which one of the following pairs of species have the same bond order ?
- O2, NO+
- CN-, CO
- N2, O2-
- CO, NO
Answer
(2) CN-, CO
Solution
Bond order = 12(Nb - Na)
O2 (16 e⁻) = 2; NO+ (14 e⁻) = 3
CN- (14 e⁻) = 10-42 = 3; CO (14 e⁻) = 3
N2 (14 e⁻) = 3; O2- (17 e⁻) = 1.5
CO = 3; NO (15 e⁻) = 2.5
∴ CN- and CO (isoelectronic) have the same bond order, 3.
Answer: (2)