Question

The size of the species $I,I^{-}$ & $I^{+}$ follows the order:

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

Answer 1

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

If we have an element X and the species $X^{+}$ and $X^{-}$, the trend in size generally followed is: $X^{-}>X>X^{+}$.

This is because the anion will have an extra electron to accomodate making the size of the ion to be bigger than the neutral atom. On the other hand, the cation is generally smaller due to the increase in the effective nuclear charge.