Question

The isoelectronic set of ions is:
1. N^3-, O^2-, F^- and Na⁺
2. N^3-, Li⁺, Mg²⁺ and O^2-
3. F^-, Li⁺, Na⁺ and Mg²⁺
4. Li⁺, Na⁺, O^2- and F^-

Answer 1

Correct Answer - Option 1 : N^3-, O^2-, F^- and Na⁺

Concept:

Atomic number of N, O, F and Na are 7, 8, 9 and 11 respectively. Therefore, total number of electrons in each of N^3-, O^2-, F^- and Na⁺ are 10 and they are isoelectronic.

Isoelectronic refers to two atoms, ions or molecules that have the same electronic structure and the same number of valence electrons. This term means "equal electric" or "equal charge". Isoelectronic chemical species typically display similar chemical properties.

The ionic radii of isoelectronic species increase with a decrease in the magnitudes of nuclear charge.

The arrangement of the given species in order of their increasing nuclear charge is as follows:

N^3- < O^2- < F^– < Na⁺

The arrangement of the given species in order of their increasing ionic radii is as follows:

Na⁺ < F^– < O^2- < N^3-

Thus, option (a) is the correct answer.