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Assertion: Nuclei above bismuth-209 are ...

Assertion: Nuclei above bismuth-209 are unstable irrespective o f their N : Z ratio.
Reason: The force of repulsion between protons is greater than the attractive force between nucleons in nuclei above bismuth-209.

A

If both assertion and reason are correct and reason is a correct explanation o f the assertion.

B

If both assertion and reason are correct but reason is not the correct explanation o f assertion.

C

If assertion is correct but reason is incorrect.

D

If assertion is incorrect but reason is correct

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both the assertion and the reason provided. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "Nuclei above bismuth-209 are unstable irrespective of their N:Z ratio." - This means that no matter how many neutrons (N) are present compared to protons (Z) in these nuclei, they remain unstable. 2. **Analyzing the Reason**: - The reason given is that "The force of repulsion between protons is greater than the attractive force between nucleons in nuclei above bismuth-209." - In atomic nuclei, protons repel each other due to their positive charge, while they are held together by the strong nuclear force, which is an attractive force acting between all nucleons (protons and neutrons). 3. **Explaining the Relationship**: - As we move to heavier elements (above bismuth-209), the number of protons increases significantly. - The electrostatic repulsion between these protons also increases, which can lead to instability. - The strong nuclear force, while still present, may not be sufficient to overcome the increasing repulsive forces due to the high number of protons. 4. **Conclusion**: - Since the assertion is true (nuclei above bismuth-209 are indeed unstable regardless of the N:Z ratio) and the reason provided correctly explains why this is the case (the repulsive forces among protons outweigh the attractive forces), both the assertion and reason are correct. - Therefore, the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion. ### Final Answer: Both the assertion and reason are correct, and the reason is the correct explanation of the assertion. ---
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