R.A.+Milikan

Problems He Had: He did not calculate the mass of an electron in today's standard atomic mass unit (amu).
 * Atomic Theory**: He belived that the atom contains three differnt particles: The proton, electron, and nuetron. From experiments of earlier scientists, he knew that the mass of an electron was at least 1000 times less than that of a proton and that the electron had a negitive charge, as opossed to the positive charge of a proton.
 * New Discoveries** : With his oil dropping experiment, he discovered the charge of an electron to be 1.59 x 10 to the -19 and he found that the mass of the electron is 9.11 x 10 to the -28 grams.