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460
Democritus; Creator of the Atom
Democritus was born around 460 B.C. He is credited with the creation of the idea of an atom. Democritus said that atoms were 1: Indestructable
2: Solid, but invisible
3: They are homogeneous
4: that they differ in size, shape, mass, arrangemnt...ect -
Period: 460 to
Atomic Timespan
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Dalton's Atom
John Dalton; born 1803 A.D. Dalton was the first guy in history to break down the atom and come up with his own "Atomic Theory". His theory states that all elements are made of atoms. Secondly, is that one atom from an element is equal in mass to another from the same element. Thirdly, was that no two elements had the same atomic mass. -
J.J Thomson
discovered the electron and stated that these corpuscles were dotted on the atom, and might even comprise all matter within the atom! He founded the plum-puddin model. -
Max Planck
Created the quantum theory -
Albert Einstein
Said that light was made up of different particals that behaved completely different than a different type of light particle. He also came up with the theory of relativity -
Robert Millikan
found the negative charge of an electron -
Rutherford's Planetary Model
He used the results of his Gold foil theory to determine that there is a nucleas inside of the atom, and that electrons are going around it a lot like a planetary system. -
Gold Foil Experiment
the gold foil experiment was conduted by Rutherford, to find out how atoms react to alpha particles. In the experiment, Rutherford passed alpha particles through a peice of gold foil. He recorded the data on where the particles landed. some Particles were deflected a little, and some were completely reflected! This created the theory that an atom had a nucleas. -
Bohrs Energy Levels
Niels Bohr, born 1922. Bohr came up with the theory that electrons existed in different levels, and never between them. He stated that when an electron drops from a higher energy level in the "valance shell,” the electron would emit light. He also proposed that the outer levels can hold more electrons that the inner levels. His model was the basis for Quantum Mechanics. -
Chadwick
Discoverd the neutrally charged neutron -
Otto Hahn, Lise Meitner
Found out about fission. Fission is when an atoms nucleas spits and forms two separate nuclei. -
Orbitals
an orbital is the region of space an electron can be found in... there are many different types of orbitals, but the shape depends on the electron configuration. DONT KNOW THE DATE -
Electron Cloud
The final model of the atom is called The Electron Cloud modle. The creation of this model can not be to any one scientist, but many. This model is A nucleas, surrounded by a soft cloud of electrons, that take it's shape depending on it's orbital and energy level. DONT KNOW THE DATE -
Aufbau Diagram
The aufbau diagram is used to find where the electrons would be found in an orbital. The diagram has to do with electron configuration, and how atoms combine to create solutions. In each slot of the diagram, you would put an "up-spin and down-spin" which is electrons taking up the space of an orbital and energy level. DONT KNOW THE DATE -
Hunds Rule
The Hunds rule basically states that you have to fill each orbital of an energy level with one "up-spin" before you add a "down-spin" to correspond with it. DONT KNOW THE DATE -
Paulis Rule
This rule states that an orbital will either contain 0, 1, or 2 electrons at most. And that if there are 2 electrons, that they are opposite spins. DONT KNOW THE DATE -
Aufbaus Rule
Aufbaus rule states that you start from the lowest energy level ad work your way up when using the aufbau diagram. DONT KNOW THE DATE