In a radioactive decay, neither the atomic number nor the mass number changes. Which of the following is emitted in the decay?

Photon

The correct answer is Option (4) → Photon

Explanation:

In a radioactive decay where neither the atomic number nor the mass number changes, it means that there is no change in the nucleus composition (no protons or neutrons are added or removed).

This occurs during the emission of a photon (specifically a γ-ray), which represents the transition of the nucleus from an excited state to a lower energy state.

Correct statement: Photon.