Question

The hardest lanthanide element is

• A. $Sm$
• B. $La$
• C. $Gd$
• D. $Dy$

Answer 1

Answer: (C)

$Gd$

Answer 2

Hardest lanthanide element is lutetium $\left({ }_{71} Lu \right)$. But among the given options gadolinium (Gd) is the hardest lanthanoid.

Hardness of few lanthanide elements on vicker's scale is given below.