Electrons are negatively-charged particles and are found outside the nucleus of the atom, They interact with other electrons of other atoms that result to different properties of atoms. They also determine the charge of the atom, or more preferably, the ion. For a neutral atom, they have the same number as that of the protons. Protons are positively-charged particles and are found inside the nucleus along with the neutrons. Protons and neutrons are collectively called nucleons. Protons determine the atomic number of the atom. Neutrons, on the other hand, are neutrally-charged particles and are found inside the nucleus. Along with the proton, they constitute the mass of the whole atom. Atoms of the same element but with a different number of neutrons are called isotopes.