Q.

Which one of the following pairs of species have the same bond order         [2017]

1 O2,NO+  
2 CN-,CO  
3 N2,O2-   
4 CO,NO  

Ans.

(2)

Molecular orbital electronic configurations and bond order values are:

O2(16):σ1s2,σ*1s2,σ2s2,σ*2s2,σ2pz2,π2px2=π2py2,π*2px1=π*2py1

B.O.=12(Nb-Na)=12(10-6)=2

NO+ (14):σ1s2,σ*1s2,σ2s2,σ*2s2,σ2pz2,π2px2=π2py2

B.O.=12(10-4)=3

CN- (14):σ1s2,σ*1s2,σ2s2,σ*2s2,π2px2=π2py2,σ2pz2

B.O.=12(10-4)=3

CO(14):σ1s2,σ*1s2,σ2s2,σ*2s2,π2px2=π2py2,σ2pz2

B.O.=12(10-4)=3

N2 (14):σ1s2,σ*1s2,σ2s2,σ*2s2,π2px2=π2py2,σ2pz2

B.O.=12(10-4)=3

O2- (17):σ1s2,σ*1s2,σ2s2,σ*2s2,σ2pz2,π2px2=π2py2,π*2px2=π*2py1

B.O.=12(10-7)=1.5

NO(15):σ1s2,σ*1s2,σ2s2,σ*2s2,σ2pz2,π2px2=π2py2,π*2px1

B.O.=12(10-5)=2.5