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Thompson - used magnet to deflect the rays away from the negative poles and pulled to the positive poles; NO deflection w/out magnet = must be negative; Thomson discovered electrons; plum pudding Millikan - oil drop experiment; know for measuring charge of electron; used X-rays to give oil a negative charge; sprayed oil droplets in a box; fell between charged plates where he varied the amount of current; measured time it took to fall between the plates; change of electron = 1.60 x 10 to -19 James Chadwick - discovered Neutrons Beckerel - accidentally discovered uranium exhibits radioactivity Marie and Pierre Curie - isolated radium and polonium (both are radioactive) Rutherford - discovered positively charged nucleus by shooting positive alpha particles through gold foil, most went through, some deflected; screen coated w/gunpowder and produced a flash; concluded most dense part of the atom was in the center, which he called the nucleus; nucleus is positive, protons discovered; most of the atom was empty space Democritus- coined the word ATOM form atomos meaning indivisible Lavoisier - law of conservation of matter Joseph Proust - Law of Constant Composition (Law of Definite Proportion) John Dalton - matter is made of atoms, which are indivisible; all atoms of same element are identical but differ from other elements; atoms are neither created nor destroyed in any chemical reaction Franklin - studied electricity, objects could have negative or positive charge: electron means amber; static electricity is charge in motion Crookes - studied behavior of gases in vacuum tube; cathode rays J...