Which of the following is paramagnetic?

Step-by-step solution

Paramagnetic species contains unpaired electrons in their molecular orbital electronic configuration. Molecular orbital configuration of the given species is as aligned & CO (6+8=14)= 1 s^2, * 1 s^2, & 2 s^2, * 2 s^2, 2 p_x^2 2 p_y^2, 2 p_z^2 aligned (All the electrons are paired so it is diamagneitc.) aligned & O ₂⁻(8+8+1=17) & = 1 s^2, * 1 s^2, 2 s^2, * 2 s^2, 2 p_z^2, 2 p_x^2 & 2 p_y^2, * 2 p_x^2 * 2 p_y^1 aligned It contains one unpaired electron so it is paramagnetic. aligned & CN ⁻(6+7+1=14)= same as CO & NO