Question

Which of the following has largest ionic radius?

• A. $Cs ^{+}$
• B. $Li ^{+}$
• C. $Na ^{+}$
• D. $K ^{+}$

Answer 1

Answer: (A)

Atomic and ionic radii increase from top to bottom in a group due to the inclusion of another shell at every step. Hence, $Cs ^{+}$ion will be the largest among given IA group ions,
i.e. $Na ^{+}, Li ^{+}$and $K ^{+}$.