Which of the following statements about radioactivity are correct?

Options

A. It is a nuclear property
B. It does not involve any rearragement of electrons.
C. It is not affected by the presence of other elements.
D. Its rate is affected by the change in temperature `"and"//"or"` pressure.

Answer

To determine which statements about radioactivity are correct, we will analyze each statement one by one.

### Step 1: Analyze Statement A
**Statement A:** "It is a nuclear property."
- **Explanation:** Radioactivity is indeed a nuclear property because it involves the disintegration of the nucleus of radioactive elements. For example, uranium can decay into lighter elements like thorium, emitting particles such as alpha particles, beta particles, or gamma rays in the process.
- **Conclusion:** This statement is **correct**.

### Step 2: Analyze Statement B
**Statement B:** "It does not involve any rearrangement of electrons."
- **Explanation:** This statement is also correct. Radioactivity pertains to the nucleus and does not involve the rearrangement of electrons. The process is purely nuclear, meaning that the electrons surrounding the nucleus remain unaffected during radioactive decay.
- **Conclusion:** This statement is **correct**.

### Step 3: Analyze Statement C
**Statement C:** "It is not affected by the presence of other elements."
- **Explanation:** This statement is true as well. The rate of radioactive decay of a substance, such as uranium, is not influenced by the presence of other elements. The radioactive decay is a spontaneous process that occurs independently of external factors, including other elements.
- **Conclusion:** This statement is **correct**.

### Step 4: Analyze Statement D
**Statement D:** "The rate of disintegration is affected by changes in pressure and temperature."
- **Explanation:** This statement is incorrect. The rate of radioactive decay is a constant for a given isotope and is not affected by changes in temperature or pressure. Unlike chemical reactions, where temperature and pressure can influence reaction rates, radioactivity is a nuclear process that remains constant regardless of these external conditions.
- **Conclusion:** This statement is **incorrect**.

### Final Conclusion
Based on the analysis:
- **Correct Statements:** A, B, and C
- **Incorrect Statement:** D