Question

The size of $Zr$ is very similar to:

• A. La
• B. Hf
• C. Ta
• D. W

Answer 1

Answer: (B)

Hf

Due to poor shielding effect of $4f$ electrons, the outer electrons experience more attractive force from the nucleus. Due to this attraction, the size of elements contracts. This contraction is known as Lanthanide contraction.

Due to Lanthanide contraction, the size of 5th and 6th-period transition series elements are similar. Therefore, $Zr$ and $Hf$ have a similar size.