alleryStart learning →What fixes the bond length in a hydrogen molecule?
AThe distance of lowest potential energy
BThe distance at which repulsion is zero
CThe radius of the larger atom present
DThe distance of highest kinetic energy
Answer & Solution
Correct answer: A. The distance of lowest potential energy
1. As two hydrogen atoms approach, each electron is attracted to both nuclei and the potential energy falls.
2. Push them closer still and the two positive nuclei begin to repel, so the potential energy climbs again.
3. Between those two trends lies a minimum, and the bond settles at the separation giving that minimum.
4. Repulsion is never zero at the bond length, it is merely balanced by the attractions.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 7 "Chemical Bonding and Molecular Geometry", section Formation of Covalent Bonds_
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