Question

Number of unpaired electrons present in $O_2^{2-}$ is:

• A. $0$
• B. $2$
• C. $1$
• D. $3$

Answer 1

The correct option is A $0$

Molecular orbital electronic configuration of $O_2^{2-}=\sigma 1s^2{\sigma }^{\ast }1s^2\sigma 2s^2{\sigma }^{\ast }2s^2\sigma 2p_z^2\pi 2p_x^2\pi 2p_y^{2}p{i}^{\ast }2p_x^2{\pi }^{\ast }2p_y^2$
As can be seen from molecular orbital electronic configuration, number of unpaired electrons is zero.