Question

Why are bonding molecular orbitals lower in energy than the parent atomic orbitals?

Short answer

The bonding molecular orbitals are lower in energy than the atomic orbitals because of the increased stability associated with the formation of a bond

Step-by-step solution

Definition of Parent atomic orbitals

An atomic orbital is a mathematical function in atomic theory and quantum physics that describes the location and wave-like behavior of an electron in an atom. This function can be used to determine the likelihood of locating any atom's electron in any given location surrounding the nucleus.

Explanation

In bonding molecular orbitals, the electron density lies between the two nuclei of the bonding atoms. Electrons in a parent molecular orbital that interact with two nuclei are more stable than electrons in a parent molecular orbital that connect with only one nucleus. Because the bonding molecular orbital is more stable than the parent atomic orbital, bonding molecular orbitals have a lower energy.

Therefore, Because of the enhanced stability involved with the establishment of a bond, the bonding molecular orbitals have a lower energy than the atomic orbitals.