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460
Democritus (460-370BC)
Atoms are presented as liquid, gas, and solid in the atmosphere. He thought that atoms could not be seperated and were individually created reguardless their size. -
Antoine Henri Becquerel
Becqurerel was a french proffessor and showed the instabilit of the atomic nuclei. -
Marie and Pierre Curie
Researched radioactive material and gave a better understanding for people. The Curie's worked with Baquerel -
J.J. Thomson
Thomson was an english physicist that discovered the electrons. He also used the "Plum Pudding Model" to balance and keep the charge neutral. -
John Dalton
John was and english chemist who was considered, "Father of Atomic Theory". His theory was that; all matter is made of indivisible particles called atoms, sll elemment of the same element are the same, atoms of different element are different, elements combined together in a whole x ratio, and atoms are small hard spheres "billiard ball" . -
Robert Milikan
Milikan showed that the electron charge was a single value and he used drops of oil to measure the incremental charge given on the electron. -
Ernest Rutherford
Used the "Gold Foil" to prove all the positive charge and all of the mass of the atom took up a tiny volume at the middle of the atom which shows that the volume of the atoms was empty and full of electrons. Discovered the exisitence of the nucleus by accident while trying to prove the existing of the neutron. -
Niels Bohr
Took Rutherford's theory and assumed that electrons moves in an orbit given by the energy level. -
Quantum Model
Becomes closer to where the electrons are located. explains the stability of the electrons surrounding a nucleus. -
James Chadwick
Proved the neutral force within the atom. -
Aristotle (348BC)
Aristotle was a famos philospher that though the atom was based on four elements; earth, air, fire, water .