CHM 141H Lecture Notes - Lecture 4: Cathode Ray Tube, Henri Becquerel, Robert Andrews Millikan
27 Dec 2018
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Atomic structure: electrons: j. j. thomson, a british scientist, discovered electrons in 1897, beam from cathode ray tube is deflected toward positively charged plate, atoms contain negatively charged particles (electrons) with a constant mass-to-charge ratio. Mass of an electron: robert millikan, an american physicist, determined the mass and charge of an electron with his oil-drop experiment in 1909, e = 1. 602 x 10 19 c, mass of an electron= 9. 109 x 10 28 g. Thomson"s model of the atom: plum-pudding model: e distributed throughout diffuse, positively charged sphere. Atomic structure: the nucleus: rutherford"s (new zealand) gold foil experiment, bombard a thin gold foil with particles to test thomson"s model of the atom. Chadwick named neutrons because they were electrically neutral particles having a mass slightly greater than that of protons: the nucleus: Is the positively charged center of an atom, containing nearly all of the atom"s mass.
