PYQ NEET- Classification Of Elements Periodicity L-5

Question: The species $\mathrm{Ar}, \mathrm{K}^{+}$and $\mathrm{Ca}^{2+}$ contain the same number of electrons. In which order do their radii increase? (2015)#

A) $\mathrm{K}^{+}<\mathrm{Ar}<\mathrm{Ca}^{2+}$

B) $\mathrm{Ar}<\mathrm{K}^{+}<\mathrm{Ca}^{2+}$

C) $\mathrm{Ca}^{2+}<\mathrm{Ar}<\mathrm{K}^{+}$

D) $\mathrm{Ca}^{2+}<\mathrm{K}^{+}<\mathrm{Ar}$

Answer: $\mathrm{Ca}^{2+}<\mathrm{K}^{+}<\mathrm{Ar}$#