Which statement is NOT true of molecular orbitals: Select one

A: Antibonding molecular orbitals are higher in energy than all of the bonding molecular orbitals

B. When electrons are added to orbitals of the same energy, the most stable arrangement is predicted by Hund's rule

C. the number of molecular orbitals is always equal to the number of atomic orbitals combined

D. Low-energy molecular orbitals fill before high-energy molecular orbitals fill

E. a molecular orbital can accommodate up to two electrons

A: Antibonding molecular orbitals are higher in energy than all of the bonding molecular orbitals.

Explanation:

Molecular orbital theory describes covalent bonds in terms of molecular orbitals, which result from interaction of the atomic orbitals of the bonding atoms and are associated with the entire molecule.

A bonding molecular orbital has lower energy and greater stability than the atomic orbitals from which it was formed. An antibonding molecular orbital has higher energy and lower stability than the atomic orbitals from which it was formed.

Electrons in the antibonding molecular orbital have higher energy (and less stability) than they would have in the isolated atoms. On the other hand, electrons in the bonding molecular orbital have less energy (and hence greater stability) than they would have in the isolated atoms.