Atomic TImeline
Plato 350 BCE
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Thought that all atoms were made from four fundamental solids, Earth Water, Air, and Fire. He added on to the mathematical discovery by Empedocles with the theory of forms.
Antione Lavoisior 1789
John Dalton 1803
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JJ Thompson 1897
Robert Millikan 1909
Confirmed Thompson's hypothesis The mass of an electron is at least 1000 times smaller than the lightest atom.
Sir Earnest Rutherford 1911
Concluded atoms existed in mostly an empty space with most of the mass in the middle (the nucleus)
Created the theory of the Electron and that atoms were unit formally packed spheres of positive matter. Later he also discovered the Proton.
Developed a thought that matter was composed of atoms that had different weights. Substances always broke down into the same elements in the same proportions.
Created law on Conservation Of Mass saying that Mass will stay consistent through all forms in a chemical reaction.
Democritus 442 BCE
Originated the thought saying that matter is made of smaller particles surrounded by empty space that may vary in size and shape.
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Experimenting with the burning process helped him come to this conclusion.
Studied and experimented with gasses to help him figure out that compounds always broke down the same elements.
e/m = -1.76 x 108 coulombs/g
Used ray tubes to find out that electrons and protons existed in atoms
Measured the course of charged water to fing the charge of an electron
Aimed a beam of beam of alpha particles at a gold foil to find the atoms acted as a thick net, some passed throuh while others didn't
Niels Bohr 1913
Experimented with the viscosity of water and finite altitudes.
Proposed the theory of the hydrogen atom
Sir James Chadwick 1932
Discovered the neutron (a neutrally charged particle)
Use a polonium source and a Geiger counter to find this discovery
Erwin Shrodinger 1926
WolfGang Pauli 1925
Experimented with mathematics to articulate this movement
Used Math to articulate the movement of electrons and developed the electron cloud model.
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Stated that in an atom no two electrons can occupy the same quantum state
Friedrich Hund 1927
Created the Molecular orbital theory and described the electronic structure of molecules and discovered quantum tunneling
Bibliography:
https://www.aps.org/publications/apsnews/200701/history.cfm
https://www.nobelprize.org/prizes/chemistry/1908/rutherford/biographical/
https://www.britannica.com/biography/Friedrich-Hund
https://www.khanacademy.org/science/chemistry/electronic-structure-of-atoms/history-of-atomic-structure/a/discovery-of-the-electron-and-nucleus
https://study.com/academy/lesson/the-theory-of-forms-by-plato-definition-lesson-quiz.html
https://www.iep.utm.edu/democrit/
https://www.biography.com/scientist/john-dalton
https://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm
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