Question

The lanthanoid contraction is responsible for the fact that ______.

Options

• Zr and Y have about the same radius.

• Zr and Nb have smaller oxidation state.

• Zr and Hf have about the same radius.

• Zr and Zn have the same oxidation state.

Answer 1

The lanthanoid contraction is responsible for the fact that Zr and Hf have about the same radius.

Explanation:

The lanthanoid contraction refers to the gradual decrease in atomic and ionic sizes of lanthanoids due to poor shielding by 4f electrons. As a result, hafnium (Hf), which comes after the lanthanoids, has almost the same atomic radius as zirconium (Zr), even though it is placed much lower in the periodic table.