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340
Aristotle B.C.E.
Thought matter was made up of elements - Air, earth, water, fire, and aether.
Bibliography:
"Aristotle’s Contribution | Atomic Model History." Atomic Model History. 26 Feb. 2014 -
460
Democritus B.C.E.
Democirtus contemplated the existance of particles called atoms.. This comes from the idea of unsplittable. The idea is that there is a point where things can no longer be devided into half. The atom, is that point.
Bibliography:
"Democritus." Windows to the Universe. 26 Feb. 2014 -
Dalton
Thought that matter was made up of atoms. Made a system to calculate the atomic structure of a compound.
Bibliography:
"John Dalton." Homepage of the Chemical Heritage Foundation. Chemical Heritage Foundation. 25 Feb. 2014
"Dalton's atomic theory." Dalton's atomic theory. Indiana University Northwest. 24 Feb. 2014 -
Thomson
Discovered the electron, the negatively charged part of an atom. Thought the atom was positively charged, but also had electrons orbiting the atom.
Bibliography:
"Thomson Atomic Model." Encyclopedia Britannica Online. Encyclopedia Britannica. 04 Mar. 2014 -
Rutherford
Discovered that there is a center to atoms - the nucleus, throught the gold foil experiment, where he fired radioactive particles through various thin metals, most notably gold.
Bibliography: "Rutherford - Atomic Theory." Rsg.org. 26 Feb. 2014
The Editors of Encyclopædia Britannica. "Rutherford atomic model." Encyclopedia Britannica Online. Encyclopedia Britannica. 27 Feb. 2014 -
Bohr
Suggested that electrons went around the nucleus in a fixed orbit. Famous for The Bohr Model.
Bibliography:
"Bohr Atomic Model." Abyss.uoregon.edu. 27 Feb. 2014 -
Heisenberg and Schrodinger
Discovered that electrons do not orbit around the nucleus in a neat orbit. Also they both discovered quantum mechanics.
Bibliography:
Beyler, Richard. "Werner Heisenberg (German physicist and philosopher)." Encyclopedia Britannica Online. Encyclopedia Britannica. 25 Feb. 2014
"Schrodinger/Heisenberg Atomic Model." Timeline of the Atom. 05 Mar. 2014
