principles of electric circuit , electron flow version
Look at the atomic number of the element copper (Cu). That is the number of protons in the nucleus (as well as the number of electrons). Copper is 29.
The elementary charge per proton (or electron) is 1.602x10^-19 coulomb. This is a positive charge for protons and negative for electrons. (A non-ionized atom has an equal number of neutrons and electrons, so there is no net charge.)
The copper nucleus charge is 29 x 1.602x10^-19 = 4.646x10-18 coulomb.