Proton:A subatomic particle carrying a positive electric charge, found in the nucleus of an atom. Its mass is roughly equivalent to 1 amu.
Neutron: A subatomic particle found in the nucleus of an atom. It carries no electrical charge and its mass is also roughly equivalent to 1 amu.
Electron:A subatomic particle carrying a negative electric charge. It's much lighter than protons and neutrons with a relative mass close to 0 amu.