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101
Thales of Miletus
620 BCE
He was the 1st person to investigate basic principles of the atom (beginning of atom). -
101
Democritus
440 BCE
He did a mental experiment called "Cutting the Cheese".
He mentally cut it down into halves until it couldn't get any smaller, and the smallest peice would be an atom.
He also created the 1st atomic theory. -
101
Aristotle
340 BCE
He didn't believe in the atomic theory.
More believed his ideas, than Deomocritus because of social ranking. -
101
Sir Isaac Newton (1704)
Atomic Theory: Matter is made up of atoms.
Matter is made up of solid, massy paritcles.
Atoms are held together by attraction/forces. -
101
Becquerel (1896)
He discovered radiation. -
101
Milliken (1908-1910)
He did an Oil Drip Experiment that found the charge of individual electrons. -
101
Rutherford (1911 &1919)
He also performed the Gold Foil Experiment that discovered protons and the nucleus.
In 1911 he found the nucleus.
In 1919 he found the proton. -
101
Francis Aston (1919)
He discoverd Isotopes. -
101
Erwin Schrodinger (1926)
He used math equations to find the probability that an electron would be in a certain positiion. -
101
Chadwick (1932)
He discovered the neutron. -
101
Neils Bohr (1913)
He created a theory on electrons, which means electrons have to stay in their specific orbit. -
101
John Dalton (1803)
Atomic Theory Experiment:
a) All matter is made up of tiny particles called atoms.
b) All atoms of a given element are alike, but are different from other atoms of any element.
c) Compounds are formed when atoms of different elements combnied in fixed proportions.
d) A chemical reaction involves a rearrangement of atoms, not a change in the atoms themselves.
