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400
Democritus
It was origanaly said that Leucippus, a teacher of Democritus, was responible for coming up with his the atomic therory.The year of 450 B.C. was when the model was adopted.His theory states that atoms are created indevigually and can not be sepperated.His theory proves that atoms can not be seperated. -
450
Aristotle
Aristole had his theory based on four elemnets (earth,water,fire,and air). He also discovered that you can cut up the a piece of matter as many times and it still will be the same model. -
John Dolton
Dolton was born in 1766.In 1803, Dolton's atomic theory was named after him. Dolton's theory consisted of five points, first, atoms make up an element, second, Atoms of the same element are identical, third, Atoms of different elements are differet, fourth, when two or more atoms are combined the form compounds, fifth, Atoms can not be created or destroyed, but they can only be changed. -
Heni Becquerel
He discovered radioactivity. The model was adopted for x-rays. He was primaraly responsible. He made many mistakes but through his mistakes the radioactivity was discovered. -
Henri Becquerel
Becquerel was born in 1852.He discovered an active substance in uranium called uranium X. -
J.J Thomson
J.j Thomson came up with the plum puding experiment .He also came up with the Cathode Ray Tube Experiment.His Cathode Ray Tube Experiment helped him also discover the electron.Thomson proved that atoms are uniformed. -
Marie and Perie Curie
They proved that the radiation of uranium compuond can also be measured its conditions and atomic property.Henry Becquerel was the primarily responsible. The atoms looked as if they were planets. -
Robert Millikan
Robert Millikan had done the oil-drop experiment. The experiment was adopted in 1909. J.j thomas is the primary responsible . His experiment also determines the size of the charge of an electron. -
Ernest Rutherford
Ernest Rutherford used a thin sheet of gold and shot alpha particals through it. The particals are captured by the flurescent screen. Most of the particals are scaddered but many go through the sheet of gold. Rutherford discovered the nucleus and called it the "Rutherford e- cloud model". -
Niels Bohr
Niels Bohr's model was adopted in 1915. Hecreated the Bohr Model. Through his model most of the atomic theories with out the high levels of mathmatics as the present version dose. -
Quantum Model
The quantum model was adopted in 1923This shows how like in Bohr's model it treats the atom as electrons that surround the nucleus.Also it shows the different energy levels as Bohr's eperiment but the quantum model explained the wave diffracation patternes. -
James Chadwick
James Chadwick discovered that the atomic nucleus contains a neutral particle. This was proven more than 10 years before by Ernest Rutherford.
