In which of the following species, when 1 e − is added it must be entered into gerade molecular orbital and after adding that 1 e − , total electrons in ungerade molecular orbitals is 8

Question

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Identify Orbital Symmetry: In homonuclear diatomic molecules, $σ_{g}$ (bonding), $σ_{u}$ (antibonding), $π_{u}$ (bonding), and $π_{g}$ (antibonding) determine the gerade ( $g$ ) and ungerade ( $u$ ) nature.

Count Ungerade Electrons: All four species (C₂, N₂, O₂, F₂) contain exactly 8 ungerade electrons in their filled $σ_{1 s}^{*}$ (2e⁻), $σ_{2 s}^{*}$ (2e⁻), and $π_{2 p}$ (4e⁻) orbitals.

Determine the LUMO: The incoming electron enters the Lowest Unoccupied Molecular Orbital (LUMO), which must be gerade ( $g$ ) to keep the ungerade count at 8.

Analyze each option: For C₂, the electron enters $σ_{2 p_{z}}$ ( $g$ ); for N₂ and O₂, it enters $π_{2 p}^{*}$ ( $g$ ); while for F₂, it enters $σ_{2 p_{z}}^{*}$ ( $u$ ).

Thus, the correct options are A, B, and D.

Chemistry - CHEMICAL BONDING Question with Solution | TestHub

Options:(select one or more)

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