Four diatomic species are listed below. Identilfy the correct order in which

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Four diatomic species are listed below. Identilfy the correct order in which the bond order is increasing in them:

Options

(a) NO < O₂⁻ < C₂²⁻ < He₂⁺
(b) O₂⁻ < NO < C₂²⁻ < He₂⁺
(c) C₂²⁻ < He₂⁺ < O₂⁻ < NO
(d) He₂⁺ < O₂⁻ < NO < C₂²⁻

Correct Answer:

He₂⁺ < O₂⁻ < NO < C₂²⁻

Explanation:

Bond order = Nₙ – Nₘ / 2
He₂⁺ = σ(1s)² σ*(1s) B.O. = 0.5
O₂⁻ = KKσ(2s)² σ*(2s)² σ(2pₖ)²
π(2pᵢ)² π(2pⱼ)² π*(2pᵢ)² π*(2pⱼ)¹ B.O. = 1.5
NO = KKσ(2s)² σ*(2s)²π(2pᵢ)²
π(2pⱼ)² σ(2pₖ)² π*(2pᵢ)¹ B.O. = 2.5
C₂²⁻ = KKσ(2s)² σ*(2s)²π(2pᵢ)² π(2pⱼ)² σ(2pₖ)² B.O. = 3.0

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Question Type: Memory (964)
Difficulty Level: Easy (1008)
Topics: Chemical Bonding and Molecular Structure (86)
Subject: Chemistry (2512)

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