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350
Aristotle
Noone argued with his theory. He though all matter was fire,water,earth, or air. -
Period: 350 to
Famous Dead guys
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400
Democritus
He believed everything was made of atoms. -
500
Parmedides
Parmedides believed everything was made of building blocks. -
John Dalton
1, All elements are composed of indivisible atoms.(false, nuclear reaction)2. Atoms of same element are of different elements are different. (false, isotopes, and ions)3.Atoms make compunds.4. Atoms are rearranged in chemical reactions.
Ballard Ball Model Not created, not changed, not destroyed -
Dmitri Mendeleev
He created the 1st periodic table. They were sorted by weights, and left gaps. Elements filled in gaps later. -
JJ Tomson
He discovered electrons but not details. "Cathode ray tube" (class tube of gas. This model is called the Plum-Pudding Model. It was a possitivley charged goop. -
Robert Millikan
He founds the charge and mass of a electron. It was 1/2000 Mass of atom. -
Ernest Rutherford
He found poss (protons) nucleus with electrons around. Nucleus is very tiny and dense. -
Gold-foil experiment
This experiment shot alpha particles at golden foil. They should have went straight through, but some bounded off. This showed there was a nucleaus, rest of space was empty. -
Niels Bohr
His theory was that the electrons orbited in rings. Also that they could jump orbit to orbit to emit energy. -
Chadwick
He discovered neutron. -
Manhattan Project
This project was nuclear research , created atomic bomb for WW11. This proved Daltons theory was wrong. -
Cloud model
Electrons arnt necessarily neat rings, but in different shaped clouds. This depended on energy level.
