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200
BCE - Democritus' Discovery
One of the creators of the 1st basis for the atomic theory which states that all objects are made up of little indestructible things called atoms. -
Period: 200 to
Scientist of Atomic Theory
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John Dalton
All elements are created from indestructible particles called atoms which are different from other element atoms. His theory is when atoms of different elements are joined, sperated, or rearranged chemical reactions result. -
J.J. Thompson
Invented the cathode ray. when high energy was moved from the negative cathode plate through a vacuum sealed container to a postive plate, it created a beam of electrons. -
Ernest Rutherford
Realized that the atom must have almost all of its mass concentrated at it's center, in a nucleus, with vast majority of the atom consiting of empty space. -
Neihls Bohr
Using plancks quantum theory and Rutherford's study of the nuclues in atoms, he came to the conclusion that atoms have a heavily charged nucleus with the electrons at a distance circling around it. -
Quantum - mechanical (modern) model
