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465
Democritus Theorizes The Atom
On an uknown exact date in 465 B.C. Democritus brought up the idea of this new particle. He introduced them as "atmos", particles so small that they cannot be broken down any smaller. -
John Dalton
John Dalton is an English scientist who had the first very believable atomic theory. He came up with the model called the "Billiard Ball Model." His model was still the same in saying that an atom cannot be split into anything smaller, however, he introduced some new ideas. These included that everything is made up of atoms, and that atoms are indestructible. -
Sir William Crookes
Crookes invented a vacuum tube that showed him some new things about atoms. He saw positive and negative charges within the particle beam. -
J.J. Thomson
Thomson used Crookes discoveries to come up with the Plum-Pudding model. In this model, the negatively charged particles that he discovered from Crookes discoveries were called 'raisins" and the positively charged particles were called "pudding." The raisins arer surrounded by the pudding, almost as if sitting in the pudding. -
Ernst Rutherford
Ernst Rutherford came up with the idea of the nucleus. He studdied the scattering of alpha rays and counted the number emmitted from radium of a single particle. -
Neils Bohr
Going against all known atom models. Bohr had worked with Rutherford to discover that electrons may not orbit around the nucleus. His model, known as the "Electron Cloud Model" shows that we do not know exactly where electrons are in the atom. They are basically just in a cloud somewhere in the atom. -
Quantum Theory
The "Quantum Theory is the most recent atomic theory. This theory shows that electrons are in clouds called "orbitals" (as introduced by Bohr). Also, that electrons have properties of waves. This also names the Protons, Neutrons, and electrons of atoms. Lastly, the theory introduces atomic number and mass. -
Aristotle
Aristotle believes that everything is made up of 4 elements (Earth, Wind, Water, and Fire).His ideas were very different from Democritus's, and many people respected Aristotle much ore than Democritus.
