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Period: 384 BCE to 322 BCE
Aristotle
Belived in 4 elements, fire, water, earth, air. Refuted Democritus -
Period: 370 BCE to 460 BCE
Democritus
Found atoms were simplist unit of measure -
Period: 300 BCE to 300 BCE
Aristotle
Thought if the four elements that made up everything:earth, air, fire, and water -
The phlogiston theory
It is what makes thing burn -
Period: to
Anton Laurent de La Voisier
Matter can omly change form not be destroyed -
Joseph Louis Proust
Law of Definite Proportions -
John Dalton
Made atomic theory -
Proton
The proton was found -
Periodic table
Dimitri Mendeleev crested the first periodic table organized in 7 groups -
Proton
Proton was first found -
Becquerel
Found that uranium ore is radioactive -
Electron
The mass and charge of the electron was first found by Robert Millikan. -
Atomic model
Niels Bohr crested the atomic model -
Neutrons
Neutrons were discovered by James Chadwick -
Period: to
Periodic table changes
Glenn Seaborg