Question

Which of the following pair has the same size?

• A. Fe${}^{2+}$, Ni${}^{2+}$
• B. Zr${}^{4+}$, Ti${}^{4+}$
• C. Zr${}^{4+}$, Hf${}^{4+}$
• D. Zn${}^{2+}$, Hf${}^{4+}$

Answer 1

The correct option is C Zr${}^{4+}$, Hf${}^{4+}$

$Z{r}^{+4}$ and $H{f}^{4+}$ have same size due to lanthanide contraction.

Lanthanide contraction is caused due to poor shielding effect of the $4f$ electrons.