Which of the following pairs represents isoelectronic ions

• GC Atomic Structure

Which of the following pairs represents isoelectronic ions

1. Mg²⁺, Ca²⁺
2. Na⁺, K⁺
3. K⁺, Mg²⁺
4. Ca²⁺, S^2-

Answer

Isoelectronic ions has same number of electrons.

Atomic number of Ca is 20. Ca²⁺ has 18 electrons. Atomic number of S is 16. S^2- has 18 electrons.

The correct option is D.