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400 BCE
Democritus
Democritus suggested that matter is consists of microscopic particles called "Atoms" -
300 BCE
Arisotle
Aristotle did not believe in the atomic theory, he believed that substances were brought by the elements (Fire, Water, Air, or Land). -
Aristotle Disproved
Aristotles beliefs were taught from 300 BC all the way until he was disproven in the early 1800s -
John Dalton
Dalton disproved Aristotle and he came to agree with Democritus. Matter is made up of tiny particles, atoms, and they can not be created nor destroyed. He created our first model, which was simply just a sphere -
Sphere Model
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J.J. Thomson
Thomson used the Cathode Ray Tube Experiment and he discovered that an electron measures the bending of rays which can be used to determine a charge. He also founded the "plum pudding" model. -
Plum Pudding Model
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Albert Einstein
Einstein founded the photoelectric effect, thiis showed the nature of light and demonstrated the idea that energy is quantized. -
Nuclear Model
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Ernest Rutherford
Rutherford used the gold foil expertiment, where he tried to have particles pass through gold foil. Most of them went through while a few didn't. He discovered that atoms are mostly made up of empty space with a positive core. He also created a nuclear model. -
Niels Bohr
Bohr improved the atomic model and discovered that the electrons travel in different energy levels. -
Planetary Model
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Erwin Schrodinger
Schrodinger came up with the wave equation. He used it to determine the probability of locating an electron. -
Werner Heisenberg
Heisenberg proposed the "Uncertainty Principle". Which states that you can't know both the position and the momentum of a particle at the same time. -
Quantum Model
The prevailing theory would come to be known as the "Modern Atomic Theory"