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Study the Assertion and Reason and choose the correct option.
The Zr-Hf pair of elements has the same value of atomic radii though Zr and Hf are placed in…
Assertion: The $\text{Zr}$-$\text{Hf}$ pair of elements has the same value of atomic radii though $\text{Zr}$ and $\text{Hf}$ are placed in different periods in the periodic table.
Reason: The lanthanoid contraction prevents the expected increase in atomic radii of $\text{Hf}$.
- (a)Both Assertion and Reason are true and Reason is the correct explanation for Assertion.
- (b)Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
- (c)Assertion is true and Reason is false.
- (d)Both Assertion and Reason are false.
Answer
Answer
Correct option: (a)
Answer: (a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion.
The lanthanoid contraction (poor shielding by $4f$ electrons) makes the radius of Hf almost the same as that of Zr.