Question

Given below are the two statements: one is labelled as Assertion (A) and the other is labeled as Reason (R).
Assertion (A): There is a considerable increase in covalent radius from N to P. However from As to Bi only a small increase in covalent radius is observed.
Reason (R): covalent and ionic radii in a particular oxidation state increases down the group.
In the light of the above statement, choose the most appropriate answer from the options given below:

• A. (A) is false but (R) is true
• B. Both (A) and (R) are true but (R) is not the correct explanation of (A)
• C. (A) is true but (R) is false
• D. Both (A) and (R) are true and (R) is the correct explanation of (A)

Answer 1

The Correct Option is B

Step 1. Analyze the Assertion (A): The increase in covalent radius from N to P is significant due to additional electron shells. However, from A to B, the increase in size is smaller because of the presence of poor shielding by d- and f-electrons.

Step 2. Analyze the Reason (R): The statement in (R) is generally true as covalent and ionic radii tend to increase down the group in the periodic table. However, this reason does not specifically explain the smaller increase observed from A to B.

Step 3. Conclusion: Although both statements are individually true, the reason provided does not correctly explain the observed trend in covalent radii from A to B.