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First to propose the idea of the atoms, claiming we are all made of atoms. Atomos = indivisible -
Creator of the Atomic Theory. Billiard ball theory stated:
1) All elements are made of indivisible (can't be separated) atoms (false)
2) Atoms of the same element are identical (false)
3) Atoms of different elements are different (true)
4) Atoms combine chemically to make compounds (true) -
Proposed the existence of negative electrons. Said negative electrons swam in a positively charged atom (not true) -
Did the gold foil experiment which showed that there is a positively charged small nucleus in the middle of an atom, and the rest of the space is mostly empty in an atom. -
Proposed the idea that electrons were in energy levels (true). That they orbited the nucleus like planets orbit the sun in his planetary model (not true). -
Said electrons were found in clouded orbital regions. Knew where to find electrons. -
Discovered the mass of an element's atom were not always the same. Found neutrons were neutral and in the nucleus. Isotopes = same number of protons, different neutron numbers.