Question
Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii ? ( Numbers in the parenthesis are atomic numbers ).
A.
$$Zr\left( {40} \right)\,{\text{and}}\,Nb\left( {41} \right)$$
B.
$$Zr\left( {40} \right)\,{\text{and}}\,Hf\left( {72} \right)$$
C.
$$Zr\left( {40} \right)\,{\text{and}}\,Ta\,\left( {73} \right)$$
D.
$$Ti\left( {22} \right)\,{\text{and}}\,Zr\,\left( {40} \right)$$
Answer :
$$Zr\left( {40} \right)\,{\text{and}}\,Hf\left( {72} \right)$$
Solution :
Due to lanthanoid contraction atomic radii of $$Zr$$ and $$Hf$$ is almost similar.