Among the following species N 2 ,   N 2 + , N 2 - , N 2 2 - , O 2 , O 2 + , O 2 - , O 2 2 - the number…

The molecules with unpaired electrons are paramagnetic and molecules with all electrons paired are diamagnetic. In general molecules with an even number of electrons (except $10$ and $16$ electrons) are diamagnetic

$\begin{array}{cc}{\mathrm{N}}_2& 14{\mathrm{e}}^{-}\end{array} \mathrm{diamagnetic}$

$\begin{array}{cc}{\mathrm{N}}_2^{+}& 13{\mathrm{e}}^{-}\end{array} \mathrm{paramagnetic}$

$\begin{array}{cc}{\mathrm{N}}_2^{-}& 15{\mathrm{e}}^{-}\end{array}\mathrm{paramagnetic}$

$\begin{array}{cc}{\mathrm{N}}_2^{2-}& 16{\mathrm{e}}^{-}\end{array} \mathrm{paramagnetic}$

$\begin{array}{cc}{\mathrm{O}}_2& 16{\mathrm{e}}^{-}\end{array}\mathrm{paramagnetic}$

$\begin{array}{cc}{\mathrm{O}}_2^{+}& 15{\mathrm{e}}^{-}\end{array}\mathrm{paramagnetic}$

$\begin{array}{cc}{\mathrm{O}}_2^{-}& 17{\mathrm{e}}^{-}\end{array}\mathrm{paramagnetic}$

$\begin{array}{cc}{\mathrm{O}}_2^{2-}& 18{\mathrm{e}}^{-}\end{array}\mathrm{diamagnetic}$