Question

The correct order of ionic radii for the ions s²⁻, Cl⁻, p³⁻, Ca²⁺ is ______.

Options

• Ca²⁺ > Cl⁻ > s²⁻ > p³⁻

• s²⁻ > p³⁻ > Cl⁻ > Ca²⁺

• p³⁻ > s²⁻ < Cl⁻ > Ca²⁺

• Ca²⁺ < Cl⁻ < s²⁻ < p³⁻

Answer 1

The correct order of ionic radii for the ions s²⁻, Cl⁻, p³⁻, Ca²⁺ is Ca²⁺ < Cl⁻ < s²⁻ < p³⁻.

Explanation:

(15)P³⁻, (l6)s²⁻, (17)Cl⁻, belong to 3^rd period whereas (20)Ca²⁺ belongs to the 4^th period.

These are isoelectronic ions and therefore size depends on the nuclear charge. More is the nuclear charge, smaller is the size.