Question

Why N2 is more stable than O2. Explain on the basis of Molecular Orbital Theory

Answer 1

Molecular orbitals of nitrogen and oxygen is as below:

Nitrogen molecule has 14 electrons. So the electron distributions in molecular orbital are as below

N₂ = σ1s² σ*1s² σ2s² σ*2s² σ2p_x² π(2p_y² 2p_z²)

Bond order = (No. of electrons in bonding orbitals - No. of electrons in bonding orbitals)/2
=(10-4)/2 = 3

Oxygen molecule has 16 electrons. So the electron distributions in molecular orbital are as below

O₂ = σ1s² σ*1s² σ2s² σ*2s² σ2p_x² π(2p_y² 2p_z²) π*(2p_y¹ 2p_z¹)

Bond order= (10-6)/2 = 2

As bond order of nitrogen is more than that of oxygen, nitrogen is more stable than oxygen.