Question

Which of the following represents the correct order of

stabilities ?

• A. H – He < H + He
• B. H – He > H + He
• C. H – He >$\frac{1}{2}$H₂ + He
• D. H – He is equally stable with H & He

Answer 1

Answer: (B)

H – He > H + He

Answer 2

The electron distribution in MOs in H – He $\sigma_{1s}^{2}$ ${\sigma^{*}}_{1s}^{1}$ ; BO = $\frac{1}{2}$ , hence H – He is more stable than H & He.

In H₂ , BO = 1 , hence $\frac{1}{2}$H₂ and He is more stable than H – He