Question #200364
A radioactive atom emits an alpha particle. When this occurs, what happens to the mass number of the atom? A. It increases. B. It decreases. C. It remains constant. D. One can't determine what happens to the atomic number using only the information given.
Expert's answer
Alpha particles consist of two protons and two neutrons. Protons are positively charged. When a nucleus emits an alpha particle, these changes happen the mass number decreases by 4, the atomic number decreases by 2, the nuclear charge decreases by 2.
Answer: B. It decreases
