In the following question, a Statement of Assertion (A) is given follo...
The real reason is lead has half life billions of times greater than age of universe, so appears to be more stable among other elements of higher atomic number.
In the following question, a Statement of Assertion (A) is given follo...
Answer:
Assertion: All radio-active elements are finally converted into lead.
Reason: All the elements above lead are unstable.
Explanation:
- Radioactive elements are those elements that undergo spontaneous radioactive decay, emitting radiation in the process. This decay occurs due to the instability of the atomic nucleus.
- The stability of an atomic nucleus depends on the balance between the strong nuclear force, which holds the nucleus together, and the repulsive electromagnetic force between protons. If this balance is disrupted, the nucleus becomes unstable and undergoes radioactive decay.
- The stability of an atomic nucleus is determined by its neutron-to-proton ratio. As the atomic number increases, the number of protons in the nucleus also increases. To maintain stability, additional neutrons are needed to balance the increased electromagnetic repulsion.
- However, as the atomic number increases, the stability of the nucleus decreases. This is because the repulsive electromagnetic force between protons becomes stronger, making the nucleus less stable.
- Lead (atomic number 82) is the heaviest stable element, meaning that all elements with a higher atomic number are radioactive and undergo decay.
- Therefore, the reason that all the elements above lead are unstable is correct.
- However, the assertion that all radioactive elements are finally converted into lead is incorrect. While many radioactive elements do eventually decay into lead, there are exceptions to this rule. For example, uranium-238 decays into thorium-234, which further decays into protactinium-234, and so on. These decay chains continue until stable isotopes of lead are reached.
- Hence, the assertion is false, but the reason is true.
Conclusion:
Based on the above explanation, option B is the correct answer. The assertion is false, but the reason is true.