Question

In $O_2^{-}$, $O_2$ and $O_2^{2-}$ molecular species. Find the total number of antibonding electrons

Answer 1

Answer: 21

Molecular orbital electronic configuration of these species are :
$O_2^{-}(17e^{-}):\sigma 1s^2,{\sigma }^{\ast }1s^2,\sigma 2s^2,{\sigma }^{\ast }2s^2,\sigma 2p_z^2$,
$\pi 2p_x^2=\pi 2p_y^2,{\pi }^{\ast }2p_x^2={\pi }^{\ast }2p_y^1$
$O_2(16e^{-}):\sigma 1s^2,{\sigma }^{\ast }1s^2,\sigma 2s^2,{\sigma }^{\ast }2s^2,\sigma 2p_z^2$,
$\pi 2P_x^2=\pi 2p_y^2,{\sigma }^{\ast }2p_x^1={\pi }^{\ast }2p_y^1$
$O_2^{2-}(18e^{-}):\sigma 1s^2,{\sigma }^{\ast }1s^2,\sigma 2s^2,{\sigma }^{\ast }2s^2,\sigma 2p_z^2$,
$\pi 2p_x^2:\pi 2p_y^2,{\pi }^{\ast }2p_x^2={\pi }^{\ast }2p_y^2$
Hence number of antibonding electrons are $7,6$ and $8$ respectively