Chemistry - CHEMICAL BONDING Question with Solution | TestHub
For H₂⁺, He₂⁺, B₂⁺, C₂²⁻, N₂⁺, O₂²⁺ and F₂⁻ apply three tests: P=diamagnetic; Q=the highest occupied orbital has gerade symmetry (if degenerate, the whole HOMO set has that symmetry); R=adding one electron lowers the bond order. Use standard ground-state MO orders and include core electrons. Which classifications are correct?
Options:(select one or more)
Answer:
Solution:
C₂²⁻ is N₂-isoelectronic, with paired σ HOMO; the added electron enters π* and lowers BO. O₂²⁺ is closed-shell with filled πᵤ HOMO, not g, so it fails Q; A is false. He₂⁺ has one σ* electron and is paramagnetic; addition reduces BO, giving R only. B₂⁺ has one πᵤ electron: paramagnetic, u HOMO, and electron addition raises BO, giving no tests. F₂⁻ has one σ* electron: it is paramagnetic and addition lowers BO, giving R only. Thus only B survives.
