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460 BCE
Democritus Birth
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410 BCE
Democritus Atom Model
Thought of the theory that all things are made of atoms.
Believed atoms were indivisible. -
370 BCE
Democritus Death
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John Dalton Birth
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John Dalton Atom Model
Elements are composed of atoms.
Atoms of the same elements are identical
Atoms of different elements combine in simple whole-number ratios to form chemical combined.
Chemical reactions, atoms are combined, separated, or rearranged-but never changed. -
Dmitri Mendeleev Birth
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John Dalton Death
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Eugene Goldstein Birth
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J.J Thomson Birth
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Max Planck Birth
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Robert Millikan Birth
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Ernest Rutherford Birth
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Dmitri Mendeleev Atom Model
Created the first Periodic Table -
Niels Bohr Birth
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Erwin Schrodinger Birth
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J.J Thomson Atom Model
Discovered the electron and its negative charge. -
James Chadwick Birth
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Werner Heisenberg Birth
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Ernest Rutherford Atom Model
Added the nucleus to the atom.
"Most of the particles passed through.
a few particles were deflected.
very Few were greatly deflected." -
Dmitri Mendeleev Death
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Max Planck Atom Model
The originator of the quantum theory. -
James Chadwick Atom Model
Introduced the idea of sub-energy levels.
Discovered the neutron by comparing electric charges and masses of different atoms.
The neutron is found in the nucleus. -
Eugene Goldstein Atom Model
Discovered the proton and learned about their positive charge. -
Eugene Goldstein Death
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Erwin Schrodinger Atom Model
Used mathematical equations to describe the likelihood of finding an electron in a certain place. -
Ernest Rutherford Death
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Robert Millikan Atom model
Determined the size of the charge of an electron. -
J.J Thomson Death
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Niels Bohr Atom Model
Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted. -
Max Planck Death
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Werner Heisenberg Atom Model
Discovered a key piece of the quantum theory. Created quantum machinery. -
Robert Millikan Death
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Erwin Schrodinger Death
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Niels Bohr Death
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James Chadwick Death
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Werner Heisenberg Death