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

Options

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

Answer

C

Explanation

Isoelectronic species are those which have same no. of electrons. `K^(+)= 19-1= 18, Ca^(+2) = 20- 2= 18`
`Sc^(+3) = 21- 3= 18, Cl^(-) = 17+1= 18`