Bonding and Antibonding Molecular Orbitals?

How do bonding and antibonding orbitals compare to each other with respect to the following?

• 1. energy 2. presence of nodes 3.internuclear electron density

• Answer:

  1. Electrons occupying bonding orbitals are more stable than those in anti-bonding; therefore, the anti-bonding orbitals are higher in energy. 2. Anti-bonding orbitals have more nodes than bonding. Since the anti-bonding nodes usually fall between the atoms, they do not contribute to the bonding and are called "anti-bonding". 3) I believe bonding orbitals have a higher electron density. Electrons are going to prefer filling the bonding before filling anti-bonding. If all of the anti-bonding were filled, there would be no bond and the system would collapse.