The molecular orbital configuration of the molecules given is Total no. of electrons in NO=7(N)+8(O)=15 Hence E.C. of NO=KKσ(2s)2σ*(2s)2σ2pz2 π(2px)2π(2py)2π*(2px)1 Due to presence of one unpaired electron NO is paramagnetic. Except NO all are diamagnetic due to absence of unpaired electrons.