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400 BCE
Democritus
The idea that things were made of small particles was first thought. at the time Democritus called them Atomos. They weren't advance theories, just that if you cut something enough, eventually you are left with an un cuttable particle. -
300 BCE
Aristotle
Believed that everything was made of 4 elements, earth, fire, air, water. this was believed for a very long time and took over the Atomos -
Eugen Goldstein
Discovered that matter not only had a negative charge but also a positive charge -
J.J Thompson
Discovered that atoms contained small negatively charged particles. he called them corpuscles which later became known as electrons -
Rutherford
Ernest Rutherford completed an experiment where he discovered that an atom must have a positive charge in one specific area (nucleus) -
Bohr
predicted locations of electrons within the atom and built upon the belief that most mass was within the nucleus. -
Werner Heisenberg
Worked further on quantum mechanics and found it was impossible to find where electrons would be and how fast they would be moving -
Quantum theory
Quantum theory and cloud theory are discovered showing that electrons were not particle or waves but has qualities of both