The Discovery Of The Electron

The electron was discovered in 1895 by J.J. Thomson in the form of
cathode rays, and was the first elementary particle to be identified. The
electron is the lightest known particle which possesses an electric charge. Its
rest mass is Me 9.1 x 10 -28 g, about 1/1836 of the mass
of the proton or neutron.

The charge of the electron is -e = -4.8 x 10^-10 esu