Question

Due to lanthanoid contraction:

• A. $Fe,Co,Ni$ have equal size.
• B. $Zr$ and $Hf$ have equal size.
• C. all $f$-block ions have equal size.
• D. all isometric ions have equal size.

Answer 1

The correct option is B $Zr$ and $Hf$ have equal size.

The atomic radii of 4d and 5d transition elements are nearly same because of lanthanide contraction. Because of this the radii of Hf becomes nearly equal to that of Zr.