Question

"Positive ions have smaller radii and negative ions have larger radii in comparison to the radii of their atoms". Justify the given statement.

Answer 1

Negatively charged ions (anions) have larger radii in comparison to its parent atom similarly the positively charged ions (cation) have smaller radii in comparison to its parent atom.

The cation is formed by losing one more electron from the parent atom.

Example: $Na\to N{a}^{+}+e^{-}$

Thus, the cation has more proton and less electron. Because of this, the nuclear charge attracts the electrons from the orbits causing the contraction in the size of the ion. Thus, anion has a smaller size than cation.

SImilarily in the case of an anion, the number electron is more than the number of protons. It is formed by the gain of an electron.

Example: $Cl+e^{-}\to C{l}^{-}$

As there more electrons than a proton, the electrons repel each other causing expansion in the size of an ion. Thus anion has a larger size than its parent atom.