Which of the following are isoelectronic species i.e., those having the same number of electrons? Na+ , K+ , Mg2+ , Ca2+ , S2- , Ar.



Q.22:- Which of the following are isoelectronic species i.e., those having the same number of electrons?

Na+ , K+ , Mg2+ , Ca2+ , S2- , Ar.

Answer:-
Notes:

Isoelectronic are the species having same number of electrons.
A positive charge means the shortage of an electron.



A negative charge means gain of electron.
Number of electrons in Na+ = 11-1 = 10
Number of electrons in K+ = 19-1 = 18
Number of electrons in Mg2+ = 12-2 = 10
Number of electrons in Ca2+ = 20-2 = 18
Number of electrons in S2- = 16+2 = 18
Number of electrons in Ar = 18
Hence, the following are isoelectronic species:
1) Na+ andMg2+ (10 electrons each)
2) K+, Ca2+, S2- and Ar (18 electrons each)