Which of the following has the largest ionic radius?

Among the isoelectronic ions $(O^{2-}, N^{3-}, Mg^{2+}, Na^{+})$,the ions with the least and the highest ionic radius are,respectively

How does atomic radius vary in a period and in a group? How do you explain the variation?

Arrange $K^{+}$,$Cl^{-}$,$S^{2-}$,and $Ca^{2+}$ in decreasing order of their ionic radii with an explanation.

The ionic radii of $O^{2-}, F^{-}, Na^{+}$,and $Mg^{2+}$ are in the order :

If four different elements $A, B, C$ and $D$ have electronic configurations as $A = [Ne] 3s^2 3p^4$,$B = [Ne] 3s^2 3p^5$,$C = [Ar] 3d^{10} 4s^2 4p^4$ and $D = [Ar] 3d^{10} 4s^2 4p^5$,identify the element with the largest atomic radius.