SHELL:
               Electrons: are very small particles that are part of atoms, have a mass that is 1840 times smaller tan that of the smallest atom and are negatively charge.John Thomson discovered electrons.


NUCLEUS:
                    Neutrons: are particles that together with atoms, make up the nuclei of all atoms, have a mass that is almost the same as a proton mass and have no electrical charge. They are neutral. James Chadwick discovered neutrons.

                   Protons: are particles that are part of nuclei of all atoms, have a similar mass to a hydrogen atom and have a positive electrical charge.