Question

Which of these isoelectronic species has the smallest radius?

• A. $B{r}^{-}$
• B. $S{r}^{2+}$
• C. $R{b}^{+}$
• D. $S{e}^{2-}$

Answer 1

The correct option is B $S{r}^{2+}$

For the isoelectronic species, size of the species can be given by nuclear charge, higher the nuclear charge smaller will be the size of the ion. Out of the given isoelectronic species, $S{r}^{2+}$ has the higher nuclear charge and hence, the smallest ionic radius.