An alpha particle is ejected from the nucleus of an atom. Which of the following answers describes the change in the nucleus of the atom?
Correct answer: E. The atomic number decreases by 2, and the mass number decreases by 4.
- A. The atomic number increases by 1, and the mass number remains unchanged.
- B. The atomic number increases by 1, and the mass number decreases by 4.
- C. The atomic number increases by 1, and the mass number increases by 2.
- D. The atomic number increases by 2, and the mass number increases by 4.
- E. The atomic number decreases by 2, and the mass number decreases by 4.
Explanation
Alpha emission decreases mass number by 4 and atomic number by 2 for each emitted alpha particle. Gamma emission has no effect on the parent atom. Beta emission causes an increase of proton number by 1.
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.