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440
democritus bc
He is the first to think that atoms are made of a single material that could not be cut. -
John Dalton
He published the first atomic theroy and said #1 all substances are made of atoms wich are tiny particles that can not be created, divide, or destroyed. #2 atoms of the same element are exactly alike. #3 atoms join with other atoms to make new substances. -
J.J. Thomson
he discoverd that there are tiny particles inside the atom and called this the plum pudding model. -
Period: to
the developement of the atomic theroy
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rutherford 1909
he discoverd that there are charged particles in the part of the atom. -
rutherford 1911
he went further and discoverd that there is a nucleus that is positively charged. -
schrodinger and heisenberg
these men further explained that electrons do not travle in definate paths but more in regons called electron clouds. -
Niels Bohr
bhor said that electrons move around the nucleus in certin paths, or energy levels. -
Period: to
the developemnt of the atomic theory
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Aristotle BC
He disagreed with democtrus's idea and thought that atoms could be cut.
