The following are isoelectronic ions except
The correct answer is: C
Explanation
Two or more ions are said to be isoelectronic if they have the same electronic structure and the same number of valence electrons.
Na\(^+\) = 10 electrons = 2, 8
Mg\(^{2+}\) = 10 electrons = 2,8
O\(^{2-}\) = 10 electrons = 2,8
Si\(^{2+}\) = 12 electrons = 2,8,2
\(\implies\) Si\(^{2+}\) is not isoelectronic with the rest.
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