Answer:
d. In a stable molecule having an even number of electrons, all electrons must be paired.
Explanation:
Which of the following statements relating to molecular orbital (MO) theory is incorrect?
a. Combination of two 2p orbitals may result in either σ or π MOs. TRUE. If the atomic orbitals overlap frontally, a σ MO is produced while if the atomic orbitals overlap laterally, a π MO is produced.
b. Combination of two atomic orbitals produces one bonding and one antibonding MO. TRUE. The bonding MO has less energy than the antibonding MO.
c. A bonding MO is lower in energy than the two atomic orbitals from which it is formed. TRUE. The bonding MO is more stable than the individual atomic orbitals.
d. In a stable molecule having an even number of electrons, all electrons must be paired. FALSE. Let's consider, for example, the molecular orbitals of O₂: [tex]\sigma_{2s}^{2} \sigma_{2s}^{*2} \sigma_{2pz}^{2} \pi_{2px}^{2} \pi_{2py}^{2} \pi_{2px}^{*1} \pi_{2py}^{*1}\sigma_{2pz}^{*}[/tex]
The electrons in the degenerated π* orbitals are not paired.
e. A species with a bond order of zero will not be stable. TRUE. For a species to be stable, the bond order must be higher than zero.
