Hello,

The charge of the electron is equivalent to the magnitude of the elementary charge (e) but bearing a negative sign. Since the value of the elementary charge is roughly 1.602 x 10-19 coulombs (C), then the charge of the electron is -1.602 x 10-19 C. An electron is considered nearly massless in comparison with a proton or a neutron, and the electron mass is not included in calculating the mass number of an atom.