Question

Four diatomic species are listed below in different sequences. Which of these presents the correct order of their increasing bond order ?

Answer 1

Key Idea: Bond order=Nb−Na2 He+2:(σ1s)2(σ∗1s)1 Bond order=2−12=12                              C2−2: KK(σ2s)2(σ∗2s)1(π2px)2(π2py)2(σ2pz)2 Bond order =8−22=3 O−2:KK(σ2s)2(σ∗2s)2(σ2pz)2(π2px)2 (π2py)2(π∗2px)2(π∗2py)1 Bond order=8−52=112 NO:KK(σ2s)2(σ∗2s)2(σ2pz)2(π2px)2 (π2py)2(π∗2px)1 Bond order=8−32=212 Hence, the order of increasing bond order is as:He+2(12)<O−2(112)<NO(212)<C2−2(3)