Question

Consider the following species:-

N^3–, O^2–, F^–, Na⁺, Mg²⁺ and Al³⁺

Arrange them in the order of increasing ionic radii.

Answer 1

The ionic radii of isoelectronic species increases 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⁺ < Mg²⁺ < Al³⁺

Nuclear charge = +7 +8 +9 +11 +12 +13

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

Al³⁺ < Mg²⁺ < Na⁺ < F^– < O^2– < N^3–

Answer 2

In isoelectronic species, greater the nuclear charge, lesser will be the atomic or ionic radius.
Al³⁺ < Mg²⁺ < Na⁺ < F^– < O^2- < N^3-