All large radioactive atoms decay into smaller atoms by releasing alpha particles. Each alpha particle has 2 protons, 2 neutrons, and 0 electrons. The table below describes several neutral, low-mass atoms.

A 4-column table with 4 rows, labeled Stable Isotopes of Low-Mass Elements. The first column labeled element name has entries hydrogen, helium, lithium, beryllium. The second column labeled symbol has entries H, H e, L i, B e. The third column labeled atomic number has entries 1, 2, 3, 4. The fourth column labeled number of neutrons has entries 0, 2, 4, 5.

An alpha particle is also referred to as a nucleus of which isotope?