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400 BCE
Democritus
-Atoms are "uncuttable"
-Atoms are Small, Hard particles
-Atoms constantly move -
400 BCE
Democritus Model
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John Dalton
-All substances are made up of atoms.
-Atoms of different elements are different.
-Atoms of the same element are exactly the same.
-Elements combine in specific proportions.
- He conducted experiments in combining elements. -
John Dalton Model
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JJ Thomson
-He conducted the cathode-ray experiment
-His theory of the atomic structure lead to the "plum-pudding" model.
-There are small negatively charged particles inside an atom. -
JJ Thomson Model (Plum Pudding)
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Ernest Rutherford Model
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Ernest Rutherford
-Atoms contain mostly empty space
-He conducted the gold foil experiment
-Most of an Atom's mass is in the nucleus
-There is a small, dense, positively charged nucleus -
Niels Bohr
-Electrons jump between levels from path to path
-Electrons move in empty space
-Electrons travel in definite paths. -
Neils Bohr Model
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Erwin Schrodinger and Werner Heisenberg
-Electron paths can not be predicted.
-Electrons are found in electron clouds, not paths.
-Electron paths cannot be predicted. -
Erwin Schrodinger and Wener Heisenberg Model
