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440 BCE
Democritus
-Atoms are "uncuttable"
-Atoms are small, hard particles
-Atoms constantly move -
440 BCE
Democritus Atom Model
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Period: 440 BCE to
Atomic Theory Timespan
It's the project. -
John Dalton
-All Substances are made of Atoms
-Atoms of different elements are different
-Atoms of the same element are exactly alike
-Elements combine in specific proportions
-He conducted experiments in combining elements -
Dalton Atom Model
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JJ Thomas
- He conducted the cathode-ray tube experiment
- His theory of the atomic structure lead to the "plum-pudding" model -There are small, negatively charged particles inside an atom
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Thomas Atom Model
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Ernest Rutherford
-Atoms contain mostly empty space
-Electrons move in the empty space in the atom
-He conducted the gold-foil experiment
-Most of an atom's mass is in the nucleus
-There is a small, dense, positively charged nucleus. -
Rutherford Model of an Atom
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Niels Bohr
-Electrons jump between levels from path to path
-Electrons travel in definite paths. -
Neils Bohr Atom Model
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Schrodinger and Heisenberg
-Electron Paths can't be predicted
-Electrons are found in electron clouds, not paths -
S&H Atomic Model
