Question

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

Answer 1

Most oxygen molecules are paramagnetic because the last 2 electrons go into degenerate molecular orbitals and their spins can remain parallel, generating the triplet state. However, a higher energy form, singlet oxygen, can be made in which the electrons pair up. For example in the reaction between hydrogen peroxide and sodium hypochlorite, singlet oxygen is generated

Answer 2

because last electron is in pi orbital which is singly occupied