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Jan 1, 1000
Alchemy
In alchemy, alchemists sought a universal solvent and attempted to change cheap metals into gold starting around the 1000's. The substance that the alchemists would use in this conversion of metals was called the Philosopher's stone. In 1520, alchemists wanted to find an elixir of life that would enable people to live longer and cure all ailments.
http://www.columbia.edu/itc/chemistry/chem-c2507/navbar/chemhist.html
http://www.english.upenn.edu/Projects/knarf/Contexts/alchemy.html -
John Dalton
Dalton created an modern atomic model based on experimentation. He realized that all matter is made of atoms, atoms of an element are identical, each element has different atoms, atoms of different elements combine in constant ratios to form compounds, and atoms are rearranged in reactions.
http://www.chalkbored.com/lessons/chemistry-11/atomic-models-handout.pdf
http://www.google.com/imgres?q=john+dalton&um=1&hl=en&sa=N&rlz=1R2ADFA_enUS427&biw=1366&
http://youtu.be/FxDpZ8wGgZ8 -
Periodic Table of the Elements
Dmitry Mendeleev realized that if all of the 63 known elements are arranged in order of increasing atomic weight, and their properties are repeated according to certain periodic cycles, thus creating the periodic table of elements.
http://science.discovery.com/convergence/100discoveries/big100/chemistry.html
http://www.google.com/imgres?q=Mendeleev+periodic+table+of+elements&um=1&hl=en&sa=X&rlz=1R2ADFA_enUS427&biw=1366&bih=557&tbm=isch&tbnid=5HzX5sku7FAX5M:&imgrefurl=http://www.aip.org/history/c -
Discovery of the Proton
Eugene Goldstein discovered positive particles by using a tube filled with hydrogen gas . The positive particle had a charge equal and opposite to the electron, and was named the proton.
http://www.columbia.edu/itc/chemistry/chem-c2507/navbar/chemhist.html -
Discovery of X-rays
Wilhelm Roentgen was researching the glow produced by cathode rays when he accidentally discovered x-rays. He discovered that the rays that were causing the fluorescence could also pass through glass, cardboard and walls.
http://www.columbia.edu/itc/chemistry/chem-c2507/navbar/chemhist.html
http://thelaurelhedge.blogspot.com/2010/11/whos-coming-to-dinner.html
http://www.youtube.com/watch?v=XU8nMKkzbT8&feature=player_embedded -
JJ Thomson
JJ Thompson discovered the electron. He used a cathode ray tube in his experiments, introduced an electrical charge in which the glow would bend towards the positive side to conclude that inside of atoms were negative charges, and came up with the Plum Pudding model.
http://reich-chemistry.wikispaces.com/Fall.2008.MMA.Boyle.Timeline -
Discovering the Mass of an electron
Robert Millikan discovered the mass of an electron by puting charged oil droplets into an electrically charged field. Using Thomson's mass ration, Millikan found the mass of one electron to be 9.11E-28 grams. Millikan received the 1932 Nobel Prize in Physics for this discovery.
http://www.columbia.edu/itc/chemistry/chem-c2507/navbar/chemhist.html
http://www.youtube.com/watch?v=XMfYHag7Liw&feature=player_embedded#! -
Ernest Rutherford
Rutherford's famous Gold Foil Experiment proved that the nucleus is positive and the electrons are outside the nucleus.
http://www.clickandlearn.org/gr9_sci/atoms/modelsoftheatom.html
http://www.youtube.com/watch?v=5pZj0u_XMbc&feature=player_embedded -
Bohr
In Bohr's model, electrons orbit the nucleus in shells. He also found out that electrons can be bumped up to a higher shell if hit by an electron or a photon of light.http://www.chalkbored.com/lessons/chemistry-11/atomic-models-handout.pdf
