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330
Aristotle
Rejected the idea of atoms.
Stated that elements are made up of Fire, Water, Air, and Earth.
Born in 384 B.C.
Born in Stagira, Greece -
Period: 330 to
Atomic Theory
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450
Democritus::The Atom
Democritus discovered the atom.
He states that matter is destroyed when atoms seperate.
Atoms are the smallest particles.
Born in 460 B.C.
Born in Abdera, Thrace -
Antoine Lavoisier::Law of Conservation of Mass
Law of Conservation of Mass--states that the mass of substances will remain constant no matter what processes it will go through.
Burning Chemical Experiment
Born in 1743
Born in France
Invented the balance
Discovered respiration -
Joseph Proust::Law of Definite Proportion
Definite Proportion--a chemical compound always contains the same proportions of elements.
Born in 1754
Born in Angers, France
Was a Chemical Analist -
John Dalton::Atomic Theory
Developed the framework of an atom.
The Atomic Theory--
-All elements are made of small indivisible particles called atoms.
-All atoms of the same element are the same.
-Atoms are not created, destroyed or made into other kinds of atoms during chemical reactions. They are just rearranged into new compounds.
-Compounds result from the chemical combination of a specific atoms of different elements. -Born in 1766
-Born in Cumberland, England
-Was a Meteorologist -
J.J. Thomson::Electrons
Cathode Ray Experiment-Discovered electrons through deflection of rays using elecrically charged plates and magnets.
-Born in 1856
-Born in Manchester
-Conducted his eperiment in 1897 -
Robert Millikan::Oil Drop Experiment
-Discovered mass and voltage of electrons.
-Oil Drop Experiment -Born in 1868
-Born in Illinosis, United States
-Conducted his experiment 1909 -
Ernest Rutherford::Nucleus
-Nucleus
-Gold Foil Experiment -Born in 1871
-Born in New Zealand
-Discovered nucleus -
Neils Bohr::Energy Levels
-Light Experiment
-Discovered Energy Levels -Born in 1885
-Born Coperhagen
