VITEEE 2011 Paper

Higher the bond order higher will be the stability.
When the bond order of two molecules are same, the molecule with least number of antibonding electrons is more stable. Molecular orbital configuration of H2+ is H2+ (l) = σ 1s1
BO =

1−0

2

= 0.5
Molecular orbital configuration of He2+ is
He2+ (3) = σ 1s2,σ*1s1
BO =

2−1

5

= 0.5
Hence, stability of H2+ > stability of He2+