Classification of Elements and Periodicity in Properties - Result Question 12
####12. The species $Ar, K^{+}$and $Ca^{2+}$ contain the same number of electrons. In which order do their radii increase?
[2015]
(a) $Ca^{2+}<Ar<K^{+}$
(b) $Ca^{2+}<K^{+}<Ar$
(c) $K^{+}<Ar<Ca^{2+}$
(d) $Ar<K^{+}<Ca^{2+}$
Show Answer
Solution:
(b) In isoelectronic species the radius decrease with increase in nuclear charge hence increasing order of radius is $Ca^{+2}<K^{+}<Ar$
