Question

Which of the following pairs has isoelectronic species?

• A. $N{a}^{+},K^{+}$
• B. $M{g}^{2+},C{a}^{2+}$
• C. $N^{3–},O^{2–}$
• D. $F^{–},C{l}^{–}$

Answer 1

The correct option is C $N^{3–},O^{2–}$

Atoms or ions that have the same number of electrons are known as isoelectronic species. The species $N^{3–}$ and $O^{2–}$ have ten electrons each and therefore, are isoelectronic to each other.
Hence, the correct answer is option (c).