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Dalton's Atomic Theory
By using experimental methods, Dalton was able to modify Democrius' philosophy on atoms into a scientific theory.- All elements are composed of atoms
- atoms of the same element are identical. Atoms of any one element compared to atoms of another are not identical
- atoms of different elements can physically or chemically combine in whole number ratios to make compounds. 4.Cemical reactions occur when atoms are rearranged, separated, or combined. One atom cannot be changed into another atom
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J.J. Thomson
Discovered the electron, a negativeley charged subatomic particle. By examining the behavior of a cathode ray with the positive pole of a magnet, he concluded that the cathode ray must be a stream of fast moving, negatively charged atoms. -
Curie
Polish scientist who discovered many things about radioactivity. She won the Nobel Prize for her research in radioactive elements -
Rutherford
He was a physicist from New Zealand that discovered that an atom has a small dense positively charged nucleus with electrons moving around it. Basically our modern model of the atom. -
Bohr
discovered that electrons move in fixed circles, with the nucleus at the exact center of the circle. -
Robert A. Milikan
carried out experiments to find the quantity of charge carried by an electron. Then found the mass of the electron. He then concluded thazt an electron has exactly opne unit of negative charge and its mass 1/1840 the mass of a hydrogen atom. -
Louis de Broglie
He was a French physicist that proposed that moving particles like electrons have some properties of waves. -
Erwin Schrodinger
made the electron cloud model through his description of the motion of electrons in an atom. -
James Chadwick
confirmed the existence of neutrons and that they are in the nucleus.