When the number of electrons in bonding molecular orbitals is equal to number of electrons in anti-bonding molecular orbitals bond cannot be formed between two atoms because
A) Bonding effect by the electrons in bonding M.O.s is cancelled by the antibonding effect of electrons in antibonding M.O.s
B) Antibonding effect by the electrons in antibonding orbitals is more than the bonding effect by the electrons in bonding M.O.s
C) Average energy of bonding and anti-bonding M.O.s is more than the average energy of atomic orbitals from which they are formed
D) Average energy of bonding and antibonding M.O.s is equal to the average energy of atomic orbitals from which they are formed
B and C
I get the reason for option B as anti-bonding orbitals have higher energy comparing to the bonding orbitals, so naturally their destabilizing effect must be greater than the stabilizing effect offered by the bonding orbitals.
But I really can't understand the average energy concept of orbitals as expressed in the option C . could you help clarify what exactly is the energy concept regarding the molecular orbital and atomic orbital ? and how they can be compared?
Correct me wherever I'm wrong.