The D And F Block Elements Ques 81
81. The lanthanide contraction is responsible for the fact that
[1997]
(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 states (Atomic numbers : $Zr=40, Y=39, Nb=41$, $Hf=72, Zn=30$ )
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Solution:
- (c) We know that regular decrease in the size of the atoms and ions is called lanthanide contraction. In vertical column of transition elements there is a very small change in size and some times size is found to be same from second member to third member.The similarity in size of the atoms of $Zr$ and $Hf$ is evident due to the fact of lanthanide contraction. Therefore, $Zr$ and $Hf$ both have same radius $160 pm$.
BETA
