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101
Thales of Miletus 620-546
First person to investigate basic principles of atoms. -
101
Democritus 440
Created the "Cutting the Cheese" theory by cutting an object till it couldn't get any smaller, and said the smallest part would be an atom. -
101
Aristotle 340
Didn't believe in the atomic theory, but rather the elements of earth, fire, wind and water. -
Sir Isaac Newton
Contributed to the idea that atoms are held together by attractions or forces. -
John Dalton
Atomic Theory Experiment
1) All matter is made up of tiny particles called atoms
2) All atoms of a given element are alike but are different from the atoms of any other element
3) Compounds are formedwhen atoms of different elements combbine in fixed proportions
4) A chemival reaction involes a rearrangement of atoms, not a change in the atoms themselves -
Henri Becquerel
Came up with the Uranium Experiment and discovered radio activity. -
J.J. Thomson
Discovered the electron and created the Plum-pudding model. -
Robert Millikan
Came up with the Oil Drip Experiment and found the charge of individual electrons. -
Ernest Rutherford
Came up with the Gold-Foil Experiment and theorized that the atom was mostly empty space and that all positive charge was found in the nucleus, ended up discovering the nucleus and the proton. -
Gold-Foil Experiment
Performed by Rutherford and was used to discover the proton and nucleus. -
Francis Astan
Discovered isotopes with the experiment-mass spectograph. -
Erwin Schrodinger
Came up with the Quantum Mechanical model by taking Bohr's model and adding mathematical equations to determine that electrons don't have an exact path. -
James Chadwick
Discovered the neutron. -
Niels Bohr
Came up with the Primitive hydrogen model.