Question

Which of the following ions has the smallest radius?

• A. $T{i}^{2+}$
• B. $N{i}^{2+}$
• C. $P{t}^{2+}$
• D. $Z{r}^{2+}$

Answer 1

Answer: (B)

On moving along a period, ionic radii decreases while on moving down a group, ionic radii increases. Since, $T{i}^{2+}$ and $Z{n}^{2+}$ belong to IV B group and $N{i}^{2+}$ and $P{t}^{2+}$ belong to VIII group, ionic radii of $T{i}^{2+}<Z{r}^{2+},$ and $N{i}^{2+}<P{t}^{2+}$ Further $\text{T}{\text{i}}^{\text{2+}}$ and $\text{N}{\text{i}}^{\text{2+}}$ belong to same period, hence, $\text{N}{\text{i}}^{\text{2+}}$ has the smallest radii among the given.