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300
Democritus Discovers the atom.Everything is made up of atoms!
Discovers the atom.
Everything is made up of atoms! -
300
Aristotle Disagrees with Democritus
Changes the theory of an atom! -
Period: 300 to
Scientists
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Daltons Postulates
1)All Atoms of any one element are exactly alike in all aspects; 2)Atoms of different elements have different properties 3)A compound, as distinguished from an element is composed of a certain definite integral number of atoms of each of the elements present. 4)In the chemical reactions that may occur, none of the atoms are destroyed and no new ones are created.5)When elements react, their atoms sometimes combine in more than one -
John Newlands
Publishes his version of the Periodic table -
Crookes
Used cathode rays tubes and discovered cathode rays which indicated that different atoms were of the same material. -
Thomson
Discovered the electron -
Mendeleev
First correct periodic table! -
Bohr
Discovers the proton!