Question

The size of isoelectronic species $F{}^{-}$, $Ne$ and $Na{}^{+}$ is affected by :

Answer 1

The size of isoelectronic species - F${}^{-}$, Ne and Na${}^{+}$ is affected by nuclear charge (Z).

Higher is the nuclear charge, higher will be the attraction between the nucleus and the valence electrons and lower will be the ionic size.

Thus, the ionic size of $N{a}^{+}$ is the lowest, and the ionic size of $F^{-}$ ion is the highest.