1 janv. 1803 - John Dalton

Description:

He was an English chemist, physicist, and meteorologist.
Democritus first suggested the existence of the atom but it took almost two millennia before the atom was confirmed as a fundamental chemical object by John Dalton (1766-1844). Although two centuries old, Dalton's atomic theory remains valid in modern chemical thought.
It also stated that compounds are created by combining 2 atoms and that all atoms of given elements are identical in their mass and properties.
His inspiration was the ideas of the Ancient Greeks in describing atoms as small, hard spheres that are indivisible.
Dalton theory:
matter is composed of extremely small particles called atoms
atoms are indivisible and indestructible
atoms of a given element are identical in size, mass, and chemical properties
atoms of specific elements are different than those of other elements
in a chemical reaction, atoms separate, combine and/or rearrange

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