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100
Democritus
Democritus established the atomic hypothesis, that everything is made up of atoms, which are physically indivisible that between atoms lies empty space. also that atoms are indestructible. also diffrent kinds of atoms, which differ in shape, and size. They are also always moving,answering the statement of "there can be no movement." -
100
Aristotle
Aristotle said matter was created by four elements fire, earth, air, and water. he was the first to come up with the idea of the atom and said it was the only thing that could not be split. it was proven wrong with the atom splitting power of the nuclear bomb -
John Dalton
John Dalton statded that atoms are small hard spheres. Also that they are invisible. Atoms of the same elements are the same. he also formed the atomic theory -
JJ Thomson
Thomson discovered the eledctron and theorized that atoms were neutrally charged because the amount of positive charge and negative charges cancelled each other out. Thomson also created the plum pudding or chocolate chip cookie model. it suggested that the atom was not a solid sphere -
Henri Becquerel
Becquerel discovered radioactivity. He wondered how it worked and which ways the rays went. he wanted to see if there was anything the same with X-rays and naturally occuring phosphorescence -
Marie and Pierre Curie
Marie and Pierre's discoverie was while they were studying a sample of Uranium containing an ore and pure Uranium. they noticed that the ore released a higher level of radioactivity than the pure Uranium, this is how they found Polonium and radium -
Robert Millikan
Robert Millikan found the electron charge. It answered and discovered how much a charge on an atom can effect it's gravity. The Oil Drop Experiment was done to prove this theroy. -
Ernest Rutherford
Ernest Rutherford showed that an atom has an electron cloud and that the atom looks more like a gas than a solid figure. The Ray Tube experiment was done to prove this. -
Niels Bohr
Bohr contributed to the understanding of the structure of the atom. he said that the atom was set up like the planets orbiting the sun.he thought Rutherfords model of the atom was wrong.-he did experiments on how the atom absorbed energy and the electron would jump at certain levels of the energy. -
Quantum Model
Erwin Schrodinger was the first one to come up with the Quantom model. It was founded in 1925. The Compton Effect experiment was used to prove this model. -
James Chadwick
James Chadwick, while studing in England, found the nuetron. The question was "can there be a no charge atom that has mass" He won Nobel prize for physics.
