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100
Democritus (400 BCE)
Democritus experimented and got unexpected results about the atom in year 400 BCE. It appeared too him that the atoms were enternal and so small that it was considered invisable. He also thought that all matter were made up of aoms and that atoms were homogenous, different in only shape, arrangments, position and mangnitude and atoms can't be destoryed. He thought it looked like a round sphere. -
Period: 100 to
The History of the Atom
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340
Aristotle (340 BCE)
In 340 BCE Aristotle came up with a theory to prove Democritus wrong. The theory was that atoms didn't look like a round ball but its made up of four elements. The elements are Fire, Earth, Water, and Air. it turns out that Aristotle was wrong instead. -
Dalton
In 1803 John Dalton ahd a theory that all atoms are given elelments are identical in mass and properties, the compunds are formed by a combination of two or more different kinds of atoms, and that a chemical recation is caused by the rearrangment of atoms. He also thought that atoms looked like round balls. -
Thomson
In 1897 J.J Thomson did a series of experiment and discovered electrons in atoms.He thought that atoms were spheres of postive charge with negative chargein it. The charges would be equal in magnitude which means the atoms were neutral. They call this model the Plum Pudding Model.
www.chemheritage.org/disover/online-resources/chemistyr-in-history/themes/atomic-and neuclear-sturcture/thomsonaspx. -
Rutherford
On May, 7, 1911 Ernest gathered evidence from an experiment that proved that atoms haves positive nucleus in the cente wit negative nucleus orbiting around it. He also concluded that most of atoms are made up of empty space. -
Bohr
Off of Rutherfords observation of the atom in 1913 Bohr made his own theory. He thought that instead of electrons orbiting around the nucleus any kind of way that they orbit in circles. He thought Rutherofrd was wrong because the electrons were orbiting like Rutherford said the electrons would lose energy and spiral into the nucleus. His eveidence came from a experiment of a quantized shell model. -
Heisenberg and Schrodigner
In 1926 and 1927 Heisenberg and Schrodigner had theories of atoms that is the Earth's current thought of atoms. Even though Heisenberg's theory was based on matrix mechanics and mathematical quanities and Schrodigner's was on atom's waves they both worked and were mathematically the same. They thought electrons didnt travel in definite paths around the nucleus because the exact path can't be predicted and there are regions inside the atom called the Electron Cloud.
