Question

Which of the following statement is true when a gamma decay occurs from the nucleus of an atom?

• A. Mass number is reduced by 4 and atomic number remains the same
• B. Mass number remains the same and atomic number increases by 1
• C. Mass number and atomic number are not changed
• D. Mass number is reduced by 4 and atomic number is reduced by 2

Hint:

In gamma decay, the nucleus emits high-energy photons but remains unchanged in terms of mass number and atomic number. This distinguishes gamma decay from other forms like alpha and beta decay.

Answer 1

The Correct Option is C

Gamma decay is a type of radioactive decay in which an unstable nucleus releases energy in the form of gamma radiation (high-energy photons). Unlike other types of decay, such as alpha or beta decay, gamma decay does not change the mass number or the atomic number of the nucleus. Explanation of the Options: - Option A: Mass number is reduced by 4 and atomic number remains the same - This is incorrect. This happens in alpha decay, where an alpha particle (composed of 2 protons and 2 neutrons) is emitted, causing the mass number to decrease by 4. However, in gamma decay, the mass number and atomic number remain unchange(D)
- Option B: Mass number remains the same and atomic number increases by 1 - This is incorrect. This occurs in beta-plus decay (positron emission), where a proton is converted into a neutron and a positron is emitte(D) In gamma decay, there is no change in the atomic number.
- Option C: Mass number and atomic number are not changed - This is correct. In gamma decay, the nucleus releases energy in the form of gamma rays, but there is no change in the number of protons or neutrons in the nucleus. Thus, both the mass number and atomic number remain the same.
- Option D: Mass number is reduced by 4 and atomic number is reduced by 2 - This is incorrect. This happens in alpha decay, not gamma decay. In gamma decay, the mass and atomic numbers remain unchange(D)
Therefore, the correct answer is Option (C): "Mass number and atomic number are not change(D)"