Those species which have unpaired electrons are called paramagnetic species. And those species which have no unpaired electrons are called diamagnetic species. (1) N2 has 14 electrons. Moleculer orbital configuration of N2 =σ1s2σ1s2*σ2s2σ2s2*π2px2=π2py2σ2pz2 Here no unpaired electron present, so it is diamagnetic. (2) Moleculer orbital configuration of N2+(13 electrons) =σ1s2σ1s2*σ2s2σ2s2*π2px2=π2py2σ2pz1 Here in N2+,1 unpaired electron present, so it is paramagnetic. (3) N22− has 16 electrons. Moleculer orbital configuration of N22− is σ1s2σ1s2*σ2s2σ2s2*σ2pz2π2px2=π2py2π2px1*=π2py1* Here 2 unpaired electron present, so it is paramagnetic. (4) N2−has 15 electrons. Moleculer orbital configuration of N2−is σ1s2σ1s2*σ2s2σ2s2*σ2pz2π2px2=π2py2π2px1*=π2py0* Here 1 unpaired electron present, so it is paramagnetic. (a) O22− has 18 electrons.
Moleculer orbital configuration of O22− is σ1s2σ1s2*σ2s2σ2s2*σ2pz2π2px2=π2py2π2px2*=π2py2* Here is no unpaired electron so it is diamagnetic. (b) O2−has 17 electrons. Moleculer orbital configuration of O22− is σ1s2σ1s2*σ2s2σ2s2*σ2pz2π2px2=π2py2π2px2*=π2py1* Here 1 unpaired electron present, so it is paramagnetic. (c) O2 has 16 electrons.
Moleculer orbital configuration of O2 is σ1s2σ1s2*σ2s2σ2s2*σ2pz2π2px2=π2py2π2px1*=π2py1* Here 2 unpaired electron present, so it is paramagnetic. (d) O2+has 15 electrons. Moleculer orbital configuration of O2+is σ1s2σ1s2*σ2s2σ2s2*σ2pz2π2px2=π2py2π2px1*=π2py0* Here 1 unpaired electron present, so it is paramagnetic.