Question

The size of isoelectronic species — $F^{–}$ , Ne and $N{a}^{+}$ is affected by
(a) Nuclear charge (Z )
(b) Valence principal quantum number (n)
(c) Electron-electron interaction in the outer orbitals
(d) None of the factors because their size is the same.

Answer 1

The size of an isoelectronic species increases with a decrease in the nuclear charge (Z). For example, the order of the increasing nuclear charge of $F^{–}$ , Ne, and $N{a}^{+}$ is as follows:
$F^{–}$ < Ne < $N{a}^{+}$
Z 9 10 11
Therefore, the order of the increasing size of $F^{–}$ , Ne and $N{a}^{+}$ is as follows:
$N{a}^{+}$ < Ne < $F^{–}$