The mass number of an element is NOT changed when it emits

The mass number of an element is NOT changed when it emits

Alpha and Beta radiations only
Alpha and Gamma radiations only
Beta and Gamma radiations only
Alpha, Beta and Gamma radiations
This question was previously asked in
UPSC CAPF – 2017
The mass number (A) of an element is the total number of protons and neutrons in the nucleus.
– Alpha (α) decay: Emits a ⁴₂He nucleus. The mass number decreases by 4.
– Beta (β) decay (β⁻ or β⁺ or electron capture): In β⁻ decay, a neutron turns into a proton (A remains same, Z increases by 1). In β⁺ decay, a proton turns into a neutron (A remains same, Z decreases by 1). In electron capture, a proton captures an electron to become a neutron (A remains same, Z decreases by 1). In all Beta decay processes, the mass number does NOT change.
– Gamma (γ) decay: Emits a high-energy photon. This occurs when a nucleus transitions from a higher energy state to a lower energy state. Neither the atomic number (Z) nor the mass number (A) changes during gamma decay.
Therefore, the mass number is NOT changed when Beta and Gamma radiations are emitted.
Alpha decay changes both atomic number and mass number. Beta and Gamma decay do not change the mass number.
Radioactive decay processes result in the transformation of one atomic nucleus into another or into a lower energy state. The type of decay determines how the atomic number and mass number of the nucleus change.