Question

Arrange the following in order of their increasing size:

$C{l}^{-},S^{2-},C{a}^{2+},A{r}^{3+}$

• A. $C{a}^{2+}<Ar<C{l}^{-}<S^{2-}$.
• B. $S^{2-}<Ar<C{l}^{-}<C{a}^{2+}$.
• C. $C{a}^{2+}<S^{2-}<C{l}^{-}<Ar$.
• D. None of these

Answer 1

Answer: (A)

$C{a}^{2+}<Ar<C{l}^{-}<S^{2-}$.

The increasing order of size is
$C{a}^{2+}<Ar<C{l}^{-}<S^{2-}$.

All of these are isoelectronic ions.In isoelectronic species, as the number of protons (atomic number) goes on increasing, size goes on decreasing due to stronger attraction on the electrons.