- Even the protons and neutrons in the atomic nucleus are believed to made of even smaller particles called quarks.
- The result would be a star made entirely of neutrons, and these could be packed together as closely as the protons and neutrons in an atomic nucleus.
- If conditions are right, protons and electrons then fuse into neutrons, creating a neutron star.
- The mass number gives you the total number of protons and neutrons in the nucleus of that element.
- An alpha particle consists of two protons and two neutrons; it is the nucleus of a helium atom.