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400 BCE
Democritus
First person recorded to use the word atom (atomos- invisible). He thought if you take a piece of matter and keep separating it, there will be a point when it can't be separated anymore. -
385 BCE
Aristotle
Did not believe the theory was real. He believe that everything was made up of the 4 elements, Fire, Water, Earth, Wind. -
John Dalton
First person to use Democritus' theory and use a modern diagram. His model included, All matter consists of tiny particles called atoms. Atoms are indestructible and unchangeable. Elements are classified by the weight of their atoms. When elements react, it is their atoms that have combined to form new compounds. -
Thompson's Model
Thompson's model is more complex. It is filled with electrons. He did not predict the movement of the electrons. -
Rutherford's Model
Added the nucleus. Concluded that the electrons orbit the nucleus, like a "mini solar system". -
Bohr's Theory
Bohr stated that the lower the energy, the smaller the orbit. If a orbit is filled up completely, a new orbit will begin. -
Modern
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