What is electron, proton, and neutron?

Electron- is a negatively charged subatomic particle. Electrons in atoms exist in spherical shells of various radii, revolving around the positive nucleus. The charge on a single electron is considered as the unit electrical charge. It is represented by symbol e⁻ or β⁻ .  

Proton- is a positively charged subatomic particle forming part of the nucleus of an atom and determining the atomic number of an element. It weighs 1amu.