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100
The Alchemists
One target of the alchemists was to change or "transmute" ordinary metals into valuable metals like gold. -
400
Democritus
He believed that atoms were the smallest things in the universe and that they could not be broken up. He thought that there was just empty space between the atoms, nothing else. -
John Dalton
He thought that atoms could be distinguished by their weight. His theory had a number of principle rules. -
J.J. Thomson
He discovered that there are more things inside atoms. They are now known to us as electrons. -
Ernest Rutherford
He established that the nucleus was: very dense, very small and positively charged. He also assumed that the electrons were located outside the nucleus. -
Neils Bohr
He created the Bohr model of the atom with the atomic nucleus at the centre and electrons in orbit around it, which he put in comparison to the planets orbiting the Sun.
