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335
Aristole
He stated the four elements which are fire, water, earth, and wind. His atomic theory was that all elements with atoms can't be divided. He thought that the atoms were smooth, hard balls that won't be broken into smaller pieces. -
430
Democritus
In 430 B.C. he discovered how matter was formed into small pieces, but couldn't be broken into smaller pieces. He used "atomos" which means uncuttable. He did a experiment on a seashell and kept breaking until it was powder and tried to break the powder but couldn't break it and discovered the invisible blocking block of the atom. -
Dalton
He develop the first useful theory and studied meteorogoly that water that is evaporated is an independent gas. he also developed hypothesis that the ssize of the particles must be different. -
J.J. Thompson
He was the one who discovered the electrons which have a negative charge. he made a experiment which was called the Cathode Ray Tube Experiment. He later found it the cathode rays and it contain a negtive charge and was smaller than a atom. -
Robert Millikan
He was the who made the oil drop experiment in 1909. He laater found the charge of the droplets on the electric field of the electron. -
Ernest Rutherford
He made a experiment called the gold foil experiment which contain a gold foil. He discovered the nuclear model of the atom and the splitting of the atom. -
Niels Bohr
Bohr's model is the shape of the solar system with the sun in the middle. he also suggested that the electron sjumps with the energy levels. -
Sir James Chadwick
He was the founder of the neutrons which are in the nucelus along with the protons. He also use a differnt method for looking for particle raditation
