In 1909, Jean Perrin discovered the Avogadro constant and its relationship with the gram-molecule. In that same year, Robert Millikan, an American Physicist, conducted the now famous oil drop experiment and determined the charge for a single electron, q = 1.5924 x 10-19 C (about 0.6% off the currently accepted value). Dividing the Faraday constant, F, by q, we get the Avogadro constant:
Therefore, one Faraday (units of charge per mole) is the total charge for one gram-molecule (or mole) of electrons: