Question

Highest size will be of

• A. $B{r}^{-}$
• B. $I$
• C. $I^{-}$
• D. $I^{+}$

Answer 1

The correct option is C $I^{-}$

As we move from top to bottom in a group, atomic radii increases due to increase in principal quantum number. Size of anion is greater than neutral atom because in an anion, the electrons are more than protons and so the shells are more widely spread because the repulsive force between electrons is dominant over attractive force of nucleus.
Therefore, $I^{-}$ is of highest size.