Question

The size of iso electronic 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 sizes the same.

Answer 1

The correct option is C

Electron-electron interaction in the outer orbitals

Now, for isoelectronic species, the size does not depend on nuclear charge (Z) or valence prinicipal quantum number (n) because the number of electrons are same for all.

It depends on the effective nuclear charge.

$Zeff=Z-e$

$e$ = Screening constant.

Screening constant depends on the shielding from the inner core electrons and the electron^-

Electron repulsion in the outer orbitals.

Therefore, the size of the isoelectronic species is affected by electron- electron interaction in the outer orbitals.