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400
Democritus
Called the particles of matter atoms -
John Dalton
John dalton proposed that all matter is made of atoms and that they are indivisible and indestructible. Dalton also founded the electrons. -
The light bulb
After 1,000 tries, Thomas Edison invented the light bulb -
The x-ray machine
Wilhelm Rontgen accidentally discovered an image cast from his cathode ray generator, projected beyond the range of the cathode rays. This accident created the first x-ray image. -
JJ thomson
Thompson created the Plum Pudding model, which suggested that electrons and protons were randomly placed throughout the atom. His theory was not correct, but it did help discover the nucleus, later in history. -
Ernest Rutherford
Ernest used his "gold Foil" expiriment to determine that the atom contained electrons surrounding the nucleus and some sort of positive charge in the nucleus itself.He founded the protons. -
Neils Bohr
Based on Rutherford's theory Bohr proposed that electrons travel only in certain successively larger orbits. He suggested that the outer orbits could hold more electrons than the inner ones, and that these outer orbits determine the atom's chemical properties. -
Schrondinger
Schrodinger's most important contribution to the modern atomic theory was his development of the mathmatical description that described the paths electrons would most likely follow in their orbits around the nucleus. The formulas that Schrodinger developed in 1926 were later called the basis of quantum mechanics, and he was awarded a Nobel Prize. -
James Chadwick
James Chadwick discovered a third type of subatomic particle, which he named the neutron. -
The Atomic Bomb
The Atomic Bomb was dropped on two cities of Japan to end World War II.The bombs killed as many as 140,000 people in Hiroshima and 80,000 in Nagasaki.
