Which of the following statements is true regarding the molecular orbital theory of O₂ and  ?

CONCEPT:

Molecular Orbital Theory (MOT) and Unpaired Electrons in O₂ and O₂⁻

• The molecular orbital theory explains the bonding and electronic structure of diatomic molecules, including the oxygen molecule (O₂).
• Oxygen (O₂) has a total of 16 electrons, and when arranged in molecular orbitals, it has two unpaired electrons in the π* anti-bonding orbitals. This makes O2 paramagnetic.
• When O2 gains an extra electron to form O₂⁻ (superoxide ion), this extra electron fills one of the previously unpaired π* orbitals, leaving only one unpaired electron in O2⁻.

EXPLANATION:

• Molecular orbital diagram for O₂ :
• O2 (Molecular oxygen) — Oxygen has 2 unpaired electrons in the π* anti-bonding orbitals according to molecular orbital theory, making it paramagnetic.
• O₂⁻ (Superoxide ion) — The addition of one electron to O2 results in one unpaired electron, as the added electron pairs with one of the previously unpaired electrons.

CONCLUSION:

• O2 has 2 unpaired electrons, while O2⁻ has 1 unpaired electron is the correct statement.