When a nucleus with atomic number Z and mass number A undergoes a radioactive decay process: (A) both Z and A will decrease if the process is ( ) - decay (B) Z will decrease but A will not change if process is ( ⁺ )decay (C) Z will decrease but A will not change if process is ( ⁻ )decay. (D) Z and A will remain unchanged if process is ( )-decay. Choose the correct statement :

Step-by-step solution

- (A) both Z and A will decrease if the process is a-decay: True. In a-decay, a nucleus emits an alpha particle (₂^4 He), so Z decreases by 2 and A decreases by 4. - (B) ( Z ) will decrease but (A ) will not change if process is ( ⁺ )decay: True. In ( ⁺ )decay (positron emission), a proton converts to a neutron, emitting a positron (₁^0 e). So Z decreases by 1, and A remains unchanged. - (C) ( Z ) will decrease but ( A ) will not change if process is ( ) - decay: False. In ( ) - decay (electron emission), a neutron