An atom of an element is made up of several smaller parts. We call these parts subatomic particles. Subatomic particles include protons, neutrons and electrons. Protons and neutrons can be found inside the nucleus of an atom while electrons can be found around the nucleus floating in an electron cloud. Protons will have a positive electrical charge, neutrons will have a neutral (no) charge and electrons will have a negative charge. Most of the mass of an atom comes from the neutrons and protons because electrons have such a minor impact on the overall mass of an atom.
