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What happens to the mass number and atomic number of an element when it emits γ-radiation?

Asked in NEET (Oct.) 2020 · Q-value, decay and conservation laws

Answer: (2) Mass number and atomic number remain unchanged.

Step-by-step solution

A γ-ray is a photon: it carries zero charge and zero rest mass.

Mass number counts nucleons, and no nucleon leaves the nucleus, so A is unchanged.

Atomic number counts protons, and no charge leaves the nucleus, so Z is unchanged.

γ emission only carries away excitation energy, taking the nucleus from an excited state to a lower one.

Both numbers therefore remain the same.

Why the other options are wrong

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