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

    \[~\left( \mathbf{i} \right)\text{ }\mathbf{I}\text{ }>\text{ }{{\mathbf{I}}^{-}}>\text{ }{{\mathbf{I}}^{+}}^{{}}\]


    \[\left( \mathbf{ii} \right)\text{ }\mathbf{I}+>\text{ }{{\mathbf{I}}^{-}}>\text{ }\mathbf{I}\]


    \[\left( \mathbf{iii} \right)\text{ }\mathbf{I}\text{ }>\text{ }{{\mathbf{I}}^{+}}>\text{ }{{\mathbf{I}}^{-}}\]


    \[\left( \mathbf{iv} \right)\text{ }{{\mathbf{I}}^{-}}>\text{ }\mathbf{I}\text{ }>\text{ }{{\mathbf{I}}^{+}}^{{}}\]

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

    \[~\left( \mathbf{i} \right)\text{ }\mathbf{I}\text{ }>\text{ }{{\mathbf{I}}^{-}}>\text{ }{{\mathbf{I}}^{+}}^{{}}\]


    \[\left( \mathbf{ii} \right)\text{ }\mathbf{I}+>\text{ }{{\mathbf{I}}^{-}}>\text{ }\mathbf{I}\]


    \[\left( \mathbf{iii} \right)\text{ }\mathbf{I}\text{ }>\text{ }{{\mathbf{I}}^{+}}>\text{ }{{\mathbf{I}}^{-}}\]


    \[\left( \mathbf{iv} \right)\text{ }{{\mathbf{I}}^{-}}>\text{ }\mathbf{I}\text{ }>\text{ }{{\mathbf{I}}^{+}}^{{}}\]

Option (iv) is the answer.

The size of an anion, cation, and neutral species for a given element is in this order: anion>element>cation. Because of its higher z-effective, cation has the smallest size. The positive charge is exactly proportional to z-effective, which is inversely proportional to size.

As a result, anion size > element size > cation size