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410
Democritus atom
beleived to be an idivisible peice of matter that was the root of all things -
470
Democritus (circa 470 BC)
Democritus believed that everything was made up of indivisible molecules and he called these atoms. His model is what he believed to be just a tiny divisible peice of matter. It showed that everything is made of atoms and answered the question of what is life. -
John Dalton
Dalton belived that all matter was made from indivisbe and idestructible particles called atoms. They would attain unique charecteristics and weights for different elements but attain identical charecteristics and weights for the same elements. He believe there were three forms of atoms which were simple, compound, and complex. -
Henri Beqcuerel
A physicist who was researching uranium when he discovered natural radioactivity. This allowed observservers see what happened when the atoms were effected with the radioactivity. -
J.J. Thomson
J.J. Thompson created the plum pudding model. This model shows that the atom is primarily positive but is sprinlked with tiny negatively charged particles called electrons. His experiment was bending a cathode ray tube, and bending the path of the rays with magents. -
Mary and Pierre Curie
Mary and Pierre Curie studied radioactivity and furthered its science. They discovered Radium and Polinium. This also helped observers further study the effects on the atoms. -
Robert Millikan
Millikan enhanced J.J. Thompsons model when he discovered the exact charge of the electron. He did this in his oil drop experiment. -
Ernest Rutherford
Rutherford beleived that at the center of the atom there was a small, dense positively charged nucleus. He discovered this with the alpha particle scattering gold foil experiment. He actually disproved JJ Thompsons model which he was trying to prove. -
Niels Bohr
Niels atomic model included a nucleus with electrons orbiting around it. This explained that the speed that the electron orbited at determined its energy levels.He also thought that when an electron moves from an outer orbit to an inner orbit it would emit a quantum of energy -
James Chadwick
Chadwick discovered the nuetron. His discovery added to Bohrs model by adding the nuetrons to the protons in the nucleus. -
Quantum model
The Quantum model is based on atomic theory. It helps explain observations made on complex atoms. It was made by Niels Bohr. -
Aristotle (384 BC)
This model was asopted because it described what Aristotle thought to be an atom, which was earth air wind and fire. It answered the question which was what is life made up of. It explained that these four elements were life. There were no experiments made with this
