Question

Which one pair of atoms or ions will have same configuration?

• A. $ {{F}^{+}} $ and $ Ne $
• B. $ L{{i}^{+}} $ and $ H{{e}^{-}} $
• C. $ C{{l}^{-}} $ and $ Ar $
• D. $ Na $ and $ K $

Answer 1

Answer: (C)

Chlorine has a tendency to accept one electron to acquire inert gas configuration (octet rule). Hence, it form $ C{{l}^{-}} $ ion by taking up one electron and acquires stable configuration of $ {}_{18}Ar. $ $ C{{l}^{-}}=1{{s}^{2}},2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}}=[Ar] $