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.
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