When a radioactive element emits a β-particle, the mass number of the atom will be:
Correct answer: D. Remain the same
- A. Increased by 1
- B. Decreased by 1
- C. Increased by 2
- D. Remain the same
Explanation
When a radioactive element emits a beta particle, the mass number of the atom will remain the same. A beta particle is an electron, and it has no mass. The only thing that changes when a beta particle is emitted is the atomic number of the atom. The atomic number is the number of protons in the nucleus, and it is what determines the chemical element of the atom. When a beta particle is emitted, a neutron in the nucleus decays into a proton, an electron, and an antineutrino. The proton remains in the nucleus, but the electron is emitted. This increases the atomic number of the atom by one, but the mass number remains the same.
Last updated
About Nuclear Physics
Atomic nuclei contain protons and neutrons, with nuclear size, mass defect and binding energy describing their stability. The work covers alpha, beta and gamma decay, decay equations, half-life and decay rate, along with radiation safety and medical applications such as imaging, radiotherapy and tracers.
Practise Nuclear Physics
1,254 free Nuclear Physics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.