Question

Explain the paramagnetic nature of oxygen molecule using molecular orbital theory.

Answer 1

The molecule is paramagnetic when it has unpared electron (electrons).

The Lewis structure does not represent these unpared electrons in the oxygen molecule and can not be used to describe paramagnetic properties of oxygen:

The paramangetic nature of oxygen can be explaned by Molecular orbital theory:

We can see that there are two unpared electrons on $π_{2p_x}^*,π_{2p_y}^*$ in the molecule of O₂, these unpared electrons determine paramagnetic properties of oxygen.