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Democritus (400 B.C)
Democritus was a philisipher and believed that if you cut an object into small enough pieces, that it wouldnt be able to cut it any further and called it an atom.
"Democritus Atom." Universe Today RSS. N.p., n.d. Web. 26 Feb. 2014. -
Dalton
Dalton said matter was made of tiny little particles and were like tiny balls that can't be cut. He came up with a theory that had 5 parts:
1.All matter is composed of very small particles called atoms.
2.Atoms can't be made or destroyed.
3.All atoms of the same element are identical.
4.Different elements have different types of atoms
5.Chemical reactions occur when atoms are rearranged.
His model was known as the Billard Ball model. -
Thomson
Thomson discovered that electrons were smaller than atoms and that they were indevisible. His model is a sphere with positively charged matter with electrons inside of it. He called it the Plum Pudding Model.
The Editors of Encyclopædia Britannica. "Thomson Atomic Model." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 04 Mar. 2014. -
Rutherford
Rutherford discovered that atoms had a nucleus and that positive energy was concentrated into the center of the atom in the nucleus.
http://www.britannica.com/EBchecked/topic/514258/Rutherford-atomic-model -
Bohr
Bohr said that atoms had a nucleus and that the electrons were like planets orbiting around the nucleus in a circle on around ring.He called the rings orbits and he called it the "Bohr Model". -
Schrodinger and Heisenberg
Schrodinger said theat electrons weren't in orbit but, instead were buzzing hyper-actively around the nucleus. He called their paths orbitals. They came up with the electron cloud model. -
Aristotle (384 B.C.)
Aristotle saidd that he didnt believe in an atom. He believed that everthing was made up of earth, wind, fire, and not atoms.
