Which of the following species exhibits the diamagnetic behaviour?
Which of the following species exhibits the diamagnetic behaviour?
$\mathrm{O}_2^{2-}$
$\mathrm{O}_2^{+}$
$\mathrm{O}_2$
$\mathrm{NO}$
Solution
The correct option is $\mathrm{O}_2^{2-}$
This species has $18 \mathrm{~e}^{-}$, which are filled in such a way that all molecular orbitals are fully filled, so diamagnetic.
$\mathrm{\sigma 1 s^2 \sigma^* 1 s^2, \sigma 2 s^2 \sigma^* 2 s^2, \sigma 2 p_z^2, \pi 2 p_x^2=\pi 2 p_y^2, \pi^* 2 p_x^2=\pi^* 2 p_y^2}$
Hence, (A) is correct.