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340
Aristotle
In 340BC Aristotle made it clear that he didnt belive that the world was made up of atoms. He said that they were made up of Earth, Wind, Fire, and Water. Since he said this many people belived this for many years. -
Period: 340 to
The atomic theory
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400
Democritus
In 400 BC he discovered that different types of tiny discrcte particles. Also that the properties determine the properties of matter. -
400
Alchemists
During 400-1400AD the common Alchemists wanted to transmute an element into gold. They belived there were seven main elements. They used symbols to identify there elements. Two of the most famous Alchemists were Paracelsus and Agricola. -
John Dalton
All matter is composed of atoms. Atoms cannot be made or destroyed. All atoms of the same element are identical. Different elements have different types of atoms. Chemical reactions occur when atoms are rearranged compounds are formed from atoms of the constitvents elements. -
JJ Thomson
Made of small particles. Theory: cathode raytubes -
Ernest Rutherford
Showing electrons circling around the nucleus like plantets. -
Niels Bohr
Atomic model
Electrons travel in seperate orbits. -
Albert Einstine
Albert Einstine discovered so many things throughout his life time. He made E=mc2 which is energy is mass times by the speed of light. He also created many theorys which have to do with light, gravity, energy, and matter. -
Electron Cloud Model
This model shows where the electron has been and will be. Werner Heisen Berg and Erwin Schodinger created this model -
James Chadwick
In 1932 James Chadwick discoverd the nuetron. Nuetrons help to stabalize the protons in the atoms nucleus.