Question

Although Zirconium belongs to $4d$ and Hafnium belongs to $5d$ transition series, they show similar physical and chemical properties because both

• A. belong to d-block
• B. have same number of electrons
• C. belongs to the same group of the periodic table
• D. have similar atomic radius

Answer 1

Answer: (D)

This is because the atomic radii of $4d$ and $5d$ transition elements are nearly same. This similarity in size $\left(\text{Z}\text{r}=160,\text{H}\text{f}=159\text{p}\text{m}\right)$ is due to lanthanoid contraction. Because of this contraction the radius of $\text{H}\text{f}$ becomes nearly equal to that of $\text{Z}\text{r}$ and as the properties of an element depends on its atomic radii they show similar properties.