The number of paramagnetic species among the following is B 2 , Li 2 , C 2 , C 2 - , O 2 2 - , O 2 + and He 2 +

Step-by-step solution

The species that contain unpaired electrons are paramagnetic. Electronic configuration of Li 2 molecule is σ 1   s 2 σ * 1   s 2 σ 2   s 2 . The electronic configuration of B 2 molecule is σ 1 s 2 σ ⋆ 1 s 2 σ 2 s 2 σ ⋆ 2 s 2 π 2 p x 1 = π 2 p y 1 The presence of unpaired electrons in the two π bonding molecular orbitals explains its paramagnetic nature. The electronic configuration of C 2 KK σ 2 s 2 σ * 2 s 2 π 2 p x 2 &#960