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Per NCERT Table 3.7, which element has the MOST NEGATIVE electron gain enthalpy and why is it NOT fluorine?
AF (~−500)
BI
CCl (~−349 kJ/mol). F is less negative (~−328) because adding e⁻ to the small 2p shell of F causes more e–e repulsion than in 3p of Cl
DBr
Answer & Solution
Correct answer: C. Cl (~−349 kJ/mol). F is less negative (~−328) because adding e⁻ to the small 2p shell of F causes more e–e repulsion than in 3p of Cl
Per NCERT Table 3.7 + Problem 3.7, Cl ΔₑgH ≈ −349, F ≈ −328 kJ/mol. F's 2p is small → high e–e repulsion when an electron is added.
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