(A) O₂⁻ , N₂⁺
(B) O₂⁺ , N₂²⁻
(C) O₂⁻ , N₂⁻
(D) O₂⁺ , N₂⁻
Correct Answer: O₂⁺ , N₂⁻
First consider O₂⁺.
Total electrons in O₂ = 16 So, electrons in O₂⁺ = 15
Molecular orbital configuration of O₂⁺ leaves one unpaired electron.
Bond order of O₂⁺:
Bond order = (Bonding electrons − Antibonding electrons) / 2 = (10 − 5) / 2 = 2.5
Since O₂⁺ has an unpaired electron, it is paramagnetic.
Now consider N₂⁻.
Total electrons in N₂ = 14 So, electrons in N₂⁻ = 15
Molecular orbital configuration of N₂⁻ also contains one unpaired electron.
Bond order of N₂⁻:
Bond order = (Bonding electrons − Antibonding electrons) / 2 = (10 − 5) / 2 = 2.5
Since N₂⁻ has an unpaired electron, it is also paramagnetic.
Thus, O₂⁺ and N₂⁻ have the same bond order (2.5) and both are paramagnetic.
Updated for JEE Main 2026: This PYQ is important for JEE Mains, JEE Advanced and other competitive exams. Practice more questions from this chapter.