Question

Identify from the following the isoelectronic species :

Ne, O², Na⁺ OR Ar, Cl^2-, K⁺

Answer 1

Atoms and ions having the same number of electrons are isoelectronic.

Species	No. of electrons
Ne	10
O2-	8 + 2 = 10
Na+	11 – 1 = 10
Ar	18
Cl2-	17 + 2 = 19
K+	19 – 1 = 18

Hence,

Ne, O^2-, Na⁺ are isoelectronic species.