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Question: Answered & Verified by Expert
Assertion (A) While going from left to right of the periodic table, the atomic size decreases more rapidly for the $3 d$-series compared to the $4 f$-series of elements. Reason (R) $3 d$-electrons experience lesser shielding than $4 f$-electrons.
The correct answer is
ChemistryClassification of Elements and Periodicity in PropertiesTS EAMCETTS EAMCET 2019 (06 May Shift 1)
Options:
  • A Both $(\mathrm{A})$ and $(\mathrm{R})$ are correct and $(\mathrm{R})$ is the correct explanation of (A)
  • B Both $(A)$ and $(R)$ are correct, but $(R)$ is not the correct explanation of $(\mathrm{A})$
  • C (A) is correct but (R) is not correct
  • D $(A)$ is not correct but (R) is correct
Solution:
2045 Upvotes Verified Answer
The correct answer is: Both $(\mathrm{A})$ and $(\mathrm{R})$ are correct and $(\mathrm{R})$ is the correct explanation of (A)
While going from left to right of the periodic
table, the atomic size decreases more rapidly for the $3 d$-series compared to $4 f$-series of elements.
Also, $3 d$-electrons experience lesser shielding than $4 f$-electrons.
Thus, both Assertion (A) and Reason (R) are correct and (R) is the correct explanation of (A).

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