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Problem 5 - Olympiad

A radioactive sample emits β⁻ particles. How does the mass number change during the decay?

A. Increases by 1B. Decreases by 1C. No changeD. No consistent pattern

Correct: C

In β⁻ decay, a neutron converts into a proton, emitting a β⁻ particle. Mass number (A) remains unchanged, but atomic number (Z) increases by 1.