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445
Democritus
Democritus comes up with the ideas of Atoms. Small indivisble and indestructible particles. -
Period: 445 to
Atomic Model
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Dalton's Atomic Theory
John Dalton develops an Atomic Theory that supports Democritus' theory of Atoms. -
Cathode Ray Tube
Built one of the first gas discharge tubes ("cathode ray tube"). -
Periodic Layout
Dmitri Mendeleev Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law -
Electrons!
G.J. Stoney Proposed that electricity was made of discrete negative particles he called electrons ". -
Thomson Model
After the discovery of the Electron Thomson proposed that the Nuceleus give off a positive charge while electrons send off negative charges. -
Isotopes
Soddy Observed spontaneous disintegration of radioactive elements into variants he called "isotopes" or totally new elements, discovered "half-life", made initial calculations on energy released during decay. -
Rutherford Experiment
Rutherford performed an experiment to test the amount of space or estimated size of the inside of the atom discovering that it was mostly hollow. -
Rutherford's Model
After the Gold-Foil experiment it was observed that most of the atom is mostly empty space besides the nucleus. -
Bohr Model
Bohr came up with the idea of orbitals which are circular or elipsing patterns that the electrons move around the atom. -
Electron Cloud Model
The Model was the once again changed by Schrondinger who thought that although orbitals could explain patterns of electrons it would still be impossible to direct an exact course so instead he created a model that had the possibilities of telling where an Electron could be. -
Neutrons
James Chadwick Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron. -
Atomic Bomb
With the more discoveries of the atom Albert Einstein was able to come up with a formula to create a nuclear weapon. E=mc2, was the forumla to create the deadly atom bomb.
