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
$O_2=\sigma 1s^2{\sigma }^{\ast }1s^2\sigma 2{\sigma }^2{s}^{\ast }2s^2\sigma 2p_z^2\pi 2p_x^2$
$=\pi 2p_y^2{\pi }^{\ast }2p_x^1={\pi }^{\ast }2p_y^1$
Hence, the total number of electrons in antibonding molecular orbitals of $O_2$ is $6$.