Chemistry - CHEMICAL BONDING Question with Solution | TestHub
Two homonuclear diatomic ions U₂⁺ and V₂⁻ are made from second-period atoms. Both have bond order 1.5. U has atomic number less than 8 and V has atomic number at least 8. Use π₂ₚ<σ₂ₚ for U and σ₂ₚ<π₂ₚ for V, and include the filled 1s core. Let g be the total electrons in gerade orbitals of the two ions together. Let n be the number of nodal planes containing the bond axis for EACH occupied π* orbital of V₂⁻. Which pair (g, n) follows?
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Solution:
C₂⁺ has configuration (core)(σ₂ₛ)²(σ*₂ₛ)²(π₂ₚ)³ and bond order 1.5; its gerade electrons are two in σ₁ₛ and two in σ₂ₛ, total 4. V is oxygen: O₂⁻ has bond order 1.5, with nine gerade electrons: σ₁ₛ²σ₂ₛ²σ₂ₚ²(π*₂ₚ)³. Thus g=4+9=13. Each π* orbital has one angular nodal plane containing the axis; its extra antibonding node is perpendicular to the axis and is not included in n. Hence n=1.
