Question
Discuss the formation of N2 molecule on the basis of MO theory. Predict its:
(i) Bond order
(ii) Magnetic character.
Solution
The electronic structure of nitrogen atom is 
Leaving out 4 electrons in the 1s orbital of two nitrogen atoms constituting the molecule (represented as KK), the molecular orbital energy diagram for remaining 10 electrons in nitrogen (N2) is as shown as below:
(i) Electronic configuration:
N2 : [KK (σ2s)2 (σ2s)2 (
2px)1(σ2pz)2]
(i) Bond order : Here Nh = 8 and Na = 2
The two nitrogen atoms in nitrogen molecule are linked by three covalent bonds (i.e. a triple bond).
(ii) Magnetic character: Since all the electrons are paired, nitrogen is diamagnetic.
