Question

Which of the following has the largest ionic radius?

• A. $N{a}^{+}$
• B. $K^{+}$
• C. $M{g}^{++}$
• D. $A{l}^{3+}$
• E. $C{l}^{-}$

Answer 1

The correct option is B $K^{+}$

E. $C{l}^{-}$ ion has the largest ionic radius.
The radius of cation is smaller than the radius of neutral atom whereas the radius of anion of larger than the radius of neutral atom.
Also on moving down a group, the atomic / ionic radii increases and on moving from left to right in a period, the atomic / ionic radii decreases.