Which one of the following sets of ions represents a collection of isoelectronic species? (Atomic nos.: F = 9, Cl = 17, Na = 11, Mg = 12, Al = 13, K = 19, Ca = 20, Sc = 21)

Q. Which one of the following sets of ions represents a collection of isoelectronic species? (Atomic nos.: F = 9, Cl = 17, Na = 11, Mg = 12, Al = 13, K = 19, Ca = 20, Sc = 21)

A.            K+, Ca2+, Sc3+, Cl–

B.            Na+, Ca2+ , Sc3+, F–

C.            K+, Cl–, Mg2+, Sc3+

D.            Na+, Mg2+, Al3+, Cl–

Answer: K+, Ca2+, Sc3+, Cl–