Question

The diamagnetic species among the following is

• A. $O_2^{+}$
• B. $O_2^{-}$
• C. $O_2$
• D. $O_2^{2-}$

Answer 1

The correct option is D $O_2^{2-}$

The molecular orbital diagram of $O_2$ is,

The species will be diamagnetic if there is no unpaired electron present.
In $O_2^{+}$ , one unpaired electron will be there.
In $O_2^{-}$ also one unpaired electron will be there.
In $O_2$ , two unpaired electron will be there.
But, in $O_2^{2-}$ no unpaired electron is present, so it will be diamagnetic in nature.