Question

Which of the following is the correct order of size of the given species?

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

Answer 1

The correct option is D $I^{-}>I>I^{+}$

A cation is smaller and anion is larger in size than its parent atom.

$I^{-}$, $I$ and $I^{+}$ have 53 protons each. They have 54, 53 and 52 electrons respectively.

In $I^{-}$, fewer protons are acting on more electrons. Hence it has a larger size. In $I^{+}$, more protons are acting on fewer electrons. Hence it has a smaller size.