Question

QUESTION 10 According to the molecular orbital model, which of these is least stable? A. He2 B. Li2 C. B2 D. C2 E. NO (Assume MO energy levels are the same as in N2)

Answer 1

He2

Explanation:

In the He2 molecule, there are eight electrons from the four electrons occupying the orbitals in the two helium atoms. These electrons are arranged into one bonding and one anti bonding orbital containing two electrons each. Eventually, the number of electrons occupying bonding molecular orbitals equals the number of electrons occupying anti bonding molecular orbitals hence the net bond energy is zero and the molecule is very unstable.