Question

According to $ MOT $ , $ O_2 $ is paramagnetic in nature, what is the number of electrons in antibonding molecular orbitals?

• A. 8
• B. 7
• C. 9
• D. 6

Answer 1

Answer: (D)

Molecular orbital electronic configuration of
$O_2 = \sigma 1s^2 \sigma^* 1s^2 \sigma 2 \sigma^2s ^* 2s^2 \sigma 2 p_z^2 \pi2p_x^2$
$ = \pi 2p_y^2 \pi^* 2p_x^1 = \pi^* 2p_y^1$
Hence, the total number of electrons in antibonding molecular orbitals of $O_2$ is $6$.