In $N_{2}^{-}$ total electrons $=14+1=15$ Electronic configuration of $N_{2}^{-} \sigma 1 s^{2}, \hat{\sigma} 1 s^{2}, \sigma 2 s^{2}, \widehat{\sigma} 2 s^{2}, \sigma 2 p_{x}^{2}, \pi 2 p_{y}^{2} \approx \pi 2 p_{z}^{2}, \star{\pi} 2 p_{z}^{1}$
Due to presence of one unpaired electron, it shows paramagnetic character.