Q9 · CSIR NET Chemistry, June 2019
Paper: CSIR NET June 2019 · Subject: Physical Chemistry · Chapter: Atomic and Molecular Term Symbol · Topic: Term Symbols Atoms · Marks: 2 · Difficulty: Easy
the term symbol for ground state dinitrogen cation radical ( $\mathrm{N}_{2}^{+}$) is
(a)${ }^{2} \Pi_{u}$
(b)${ }^{2} \Sigma_{\mathrm{u}}^{-}$
(c)${ }^{2} \Pi_{\mathrm{g}}$
(d)${ }^{2} \Sigma_{\mathrm{g}}^{+}$
Answer
Answer: D ✓ checked by 4AB · confidence high
Explanation
N₂ has its HOMO at 3σg (σ2p). Removing one electron leaves (3σg)¹, giving N₂⁺ the ground term ²Σg⁺ (d).
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