-
400
Aristotle(400B.C.)
Aristotle thought each of the 4 elements proposed by Empedcles could be changed into any other element by adding heat or moisture. Aristotle used a method called transmutation this occurs whenever a substance was involved in a chemical reaction. He thought that atoms were invisible and can be morphed into different elements. -
450
Democrtitus(400B.C.)
Democtritus thought that atoms were invisible of matter that are indestructible. Democritus thought this by observing. He thought that atoms were invisible so we couldnt know for sure what they looked like. -
Dalton
Dalton states that each chemical element is composed of its own kind of atom, all of which have relatively same weight. He did a lot of expirements to get this theory. Dalton also thought that it was just a lumpy particale. -
Thomson
Thomson discovered the electron & proposed a model of the atom. His model looked like raisins stuck in a lump of pudding. He thought it looked exactly like his model. -
Rutherford
Rutherford discoered atoms are almost indestructable.he used radium as the source of alpha particles & shinned them onto the atoms in gold foil, he thought that the particles would go through the foil, but he got an exact opposite reaction. The particles bounced right off of the gold foil. He thought that the electrons spiraled around the nucleus -
Bohr
- Electrons can orbit around the nucleus but at a certain distance.
- Atoms radiate energy when a electron jumps to a lower orbit of energy, an atom absorbs energy when an electron jumps to a higher orbit of energy. Bohr came up with two diiferent typesof models, and he also did a bunch of experiments. This is who we got the Bohr diagram from.
-
Heisenberg
He discovered that a small wavelength of light is needed to view an electron. The method he used was theories from observations. His atom looked like a beehive. Famous names for his atom are "Quantum Mechanical Model" and "Electron Cloud Model". -
Schrodinger
He discovered that electrons set up standing waves when in their orbits.The method that he used were mathematical models. He thought the atom looked like a beehive. Some famous names were "Quantum Mechanical Model" and "Electron Cloud Model".
