Which of the following is diamagnetic?

Step-by-step solution

MO configuration of H ₂⁺: 1 s¹ MO configuration of He ₂⁺: 1 s², ^ * s¹ MO configuration of N ₂ : 1 s² , ซั 1 s², 2 s², * 2 s², 2 p_ y ²= 2 p_ z ², 2 p_ x ² MO configuration of O ₂ : 1 s², ^ * 1 s², 2 s², ^ * 2 s², 2 p_ x ², 2 p_ y ²= 2 p_ z ², 2 p_ y ¹= _ ^ * 2 p_ z ¹ Hence, O ₂ is paramagnetic as it possesses two unpaired electrons.