Question

Due to which property $Zr$ and $Hf$ shows similar atomic and ionic size?

• A. They are in the same group
• B. Lanthanide contraction
• C. They have similar chemical properties
• D. Diagonal relationship

Answer 1

The correct option is B Lanthanide contraction

Due to lanthanide contraction, $Zr$ and $Hf$ shows similar atomic and ionic size.
The elements which follow the lanthanoids in the third transition series are known as post lanthanoids. Due to lanthanoid contraction, the atomic radii of the elements which follow lanthanum ($Hf,Ta,W$ ,etc.) are similar to that of the elements of a previous period. $Zr-Hf$ have almost identical sizes. They have similar number of valence electrons and similar properties. They are called chemical twins.