Chemistry · Chemical Bonding and Molecular Structure

Molecular orbitals are formed when atomic orbitals combine and overlap during chemical bonding. According to molecular orbital theory, the combination of two atomic orbitals produces two molecular orbitals: one lower energy bonding molecular orbital (BMO) and one higher energy antibonding molecular orbital (ABMO). The bonding orbital increases electron density between nuclei, stabilizing the molecule, while the antibonding orbital decreases electron density between nuclei and is destabilizing. The difference in the occupation of these orbitals determines bond order and molecular stability. Why does the formation of a bonding molecular orbital stabilize a molecule compared to the parent atomic orbitals?