(A) The molecular orbital energy configuration of C22– is σ1s2,σ1s*2σ2s2,σ2s*2,π2px2=π2py2,σ2pz2 In the MO of C22– there is no unpaired electron hence it is diamagnetic (B) Bond order of O22+ is 3 and O2 is 2 therefore bond length of O2 is greater than O22+ The molecular orbital energy configuration of N2+ is
σ1s2,σ1s*2σ2s2,σ2s*2,π2px2=π2py2,σ2pz1
Bond order of N2+=
1
2
(9−4) =2.5 σ1s2,σ1s*2σ2s2,σ2s*2,π2px2=π2py2,σ2pz2,π2px*1=π2py* Bond order of N2−=
1
2
(10−5) =2.5 He2+has less energy as compare to two isolated He atoms