Statement I: The sizes of Zr and Hf are similar Statement II: Size of Hf is affected by lanthanide contraction.
(a)Statement I and II are correct and II is correct explanation of 1.
(b)Statement I and II are correct but II is not a correct explanation of 1.
(c)Statement 1 is correct and II is incorrect
(d)Statements I and II both are incorrect.
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
Zr and Hf have nearly identical radii (159 vs 156 pm) precisely because the lanthanide contraction that precedes Hf cancels the expected increase — statement II explains statement I.