The species Ar, K^(+) and Ca^(2+) contain the same number of electrons. In which order do their radii increase ?

The species Ar, K^(+) and Ca^(2+) contain the same number of electrons

1.	The species Ar, K^(+) and Ca^(2+) contain the same number of electrons. In which order do their radii increase ?
Answer» `Ca^(2+) LT K^(+) lt Ar` `K^(+) lt Ar lt Ca^(2+)` `Ar lt K^(+) lt Ca^(2+)` `Ca^(2+) lt Ar lt K^(+)` Solution :They are isoelectronic species but their NUCLEAR charges are Ca = 20, K = 19, Ar = 18. GREATER the nuclear charge of the isoelectronic species, greater is the PULL on the ELECTRONS and smaller is the size