Question

What is the change in atomic mass number when an atom emits an alpha particle?

Answer 1

___________☺✔✔✔_________

Atomic mass decreases by 2

___________☺✔✔✔_________

Answer 2

Answer:

When an atom emits an alpha particle, its atomic mass is decreased by four. This is because the atomic mass of an atom is the total number of protons and neutrons in the nucleus of that atom. The alpha particle, containing two protons and two neutrons will have an atomic mass of four and thus the atomic mass of the original atom is decreased by four. Additionally, the atomic number of the atom also decreases but only by two. This is because the atomic number of an atom is the number of protons in the nucleus. Emitting an alpha particle decreases the number of protons by two.