Which statement about beta decay is true?

• A. It increases mass number by 1
• B. Neutron becomes a Proton and emits a Beta Particle
• C. It increases atomic number by 2
• D. It emits an alpha particle

Answer: (B)

Beta decay happens when a neutron inside the nucleus turns into a proton, and a beta particle (an electron) is emitted, along with a companion antineutrino. This process leaves the mass number the same but increases the atomic number by one. The statement that a neutron becomes a proton and emits a beta particle captures exactly this transformation, so it is true. The other ideas describe different processes: increasing the mass number by one would add a nucleon, increasing the atomic number by two points to a different decay type, or emitting an alpha particle, which is a distinct form of radioactive decay.