Atomic Model and Wave-Particle Duality

Thomson’s Conclusions1. Cathode rays are charged particles (which he called"corpuscles“, and we now call electrons).2. These electrons are constituents of the atom. He trieddifferent gases in the tube and different cathode materials,but obtained the same e/m ratio: there is only one kind ofelectron in all atoms3. The e/m ratio for ions have been known (from electrolysis)and this electron e/m is 2000 times more than that forhydrogen ions, and Thomson reasoned (correctly) that thismust mean that the electron has small mass.• He got the Nobel Prize in Physics 1906.• He also proposed the ‘Plum Pudding’ or ‘raisincake’ atomic model. (Electrons are the raisin inthe positively charge cake). More on that later.Thomson 1934http://www.aip.org/history/electron/jjsound.mp3 5