The fundamental particles:
Although other atomic particles are known, the three fundamental ones are:
Protons. The proton has unit mass and carries a unit positive charge.
Neutron. The neutron has unit mass but no electrical charge.
Electron. The electron has only 1/1836 unit of mass but it carries a unit negative charge.
Thus, although we have 92 types of naturally occurring atoms, they are all built-up from different numbers of these three fundamental particles. Thus our picture of the structure of matter is as shown below.