Question

The lanthanide contraction is responsible for the fact that

• A. Zr and Y have about the same radius
• B. Zr and Nb have similar oxidation state
• C. Zr and Hf have about the same radius
• D. Zr and Zn have the same oxidation sate

Answer 1

The correct option is C Zr and Hf have about the same radius

Atomic radii down the group for transition elements first increases, becomes almost equal and then decreases. This is due to poor shielding of one of 4f electron by another in the subshell which results in greater effective nuclear charge; this effect is called lanthanide contraction.