Question

What is the condition, for a molecule do not exist?

(a) NA = NB

(b) NA > NB

(c) NA < NB

(d) NA >/< NB

This question was posed to me in unit test.

My question is based upon Bonding in Some Homonuclear Diatomic Molecules topic in division Chemical Bonding and Molecular Structure of Chemistry – Class 11

Answer 1

Right answer is (a) NA = NB

Easiest explanation: When a molecule’s bond order is equal to zero, the molecule cannot exist. The formula for finding out bond order is \(\frac{1}{2}\)(NB – NA). So NA – NB = 0, that is NA = NB. Where NA as the number of anti-bonding molecular orbitals and NB as the number of bonding molecular orbitals.