Chemistry · Periodicity of Elements and Periodic Properties
JEE Main 2024 — 30 January, Shift 1 — Question 59
Given below are the two statements, one is labelled as Assertion (A) and the other is labelled 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:
- Option A:
Both (A) and (R) are true and (R) is the correct explanation of (A)
- Option B:Correct
Both (A) and (R) are true but (R) is not the correct explanation of (A)
- Option C:
(A) is true, but (R) is false
- Option D:
(A) is false, but (R) is true
Answer: B
Step-by-step solution
From N to P, a new shell is added, so covalent radius increases significantly. From As to Bi, increase in size is small due to poor shielding by d and f electrons, known as lanthanoid contraction. Thus, assertion (A) is true.
It is also generally true that radii increase down a group. However this general statement does not explain why the increase becomes small from As to Bi. Thus, reason (R) is true but it is not the correct explanation of (A).
Thus, both (A) and (R) are true but (R) is not the correct explanation of (A).
Answer key and solution verified before publishing.
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- Exam
- JEE Main 2024
- Paper
- 30 January, Shift 1
- Subject
- Chemistry
- Chapter
- Periodicity of Elements and Periodic Properties
- Topic
- Periodicity in Physical Properties (shielding and sizes)