Which one of the following sets of ions represents the collection of isoelectronic species?

Options

A. `K^(+),Cl^(-),Mg^(2+),Sc^(3+)`
B. `K^(+),Ca^(2+),Sc^(3+),Cl^(-)`
C. `Na^(+),Ca^(2+),Sc^(3+),F`
D. `Na^(+),Mg^(2+),Al^(3+),Cl`

Answer

C

Explanation

Isoelectronic species are those which have same electrons.
`K^(+)=19-1=18, Ca^(+2)=20-2=18`
`Sc^(+3)=121-3=18, Cl^(-)=17+1=18`