Question

What is the difference between bonding and antibonding molecular orbitals?

Answer 1

Bonding orbitals place most of the electron density between the nuclei of the bonded atoms.
Antibonding orbitals place most of the electron density outside the nuclei.

Explanation:

Electrons in bonding orbitals stabilize the molecule because they are between the nuclei.

They also have lower energies because they are closer to the nuclei.

Antibonding orbitals place less electron density between the nuclei.

The nuclear repulsions are greater, so the energy of the molecule increases.

Antibonding orbitals are at higher energy levels than bonding orbitals.

Antibonding sigma orbitals have higher energy levels and less electron density between the nuclei.

Antibonding pi orbitals have higher energy levels and less electron density between the nuclei.