Question

The lanthanoid contraction is responsible for the fact that-

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

Answer 1

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

The elements of second and third transition series resembles more in properties than the elements of first and second transition series. It is due to lanthanide contraction. So, due to lanthanide contraction Zr and Hf have the same radius and also known as twins.