the proton
A proton is one of three main particles that make up the atom. The other two particles are the neutron and electron. Protons are found in the nucleus of the atom. This is a tiny, dense region at the center of the atom. Protons have a positive electrical charge of one +1 and a mass of 1 atomic mass unit amu , which is about 1.67 10 -27 kilograms. Together with neutrons, they make up virtually all of the mass of an atom. For an excellent video on protons and other fundamental particles in atoms, go to this URL:.