Question

Which of the following has the largest radius?

• A. $\text{X}$
• B. ${\text{X}}^{+1}$
• C. ${\text{X}}^{+2}$
• D. ${\text{X}}^{+3}$

Answer 1

The correct option is A

$\text{X}$

Explanation for correct option: (a)

1. The radius of cations will be always smaller than the corresponding neutral atom from which it is formed.
2. A cation is formed by the removal of one or more electrons from a neutral atom which increases the effective nuclear charge.
3. The greater the positive charge on the ion smaller will be its radius.
4. Hence here ${\text{X}}^{+3}$ is found to has a smaller radius whereas $\text{X}$ has the largest radius.

Explanation for incorrect options:

b) Here $\text{X}$ is found to have the largest radius not ${\text{X}}^{+1}$.

c) ${\text{X}}^{+2}$ is found to have a small size than $\text{X}$. Hence ${\text{X}}^{+2}$ is not the one with largest radius.

d) Here among the given options ${\text{X}}^{+3}$ is found to have a smaller radius.

Hence option (a) is correct and it is $\text{X}$ which has the largest radius.