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460
Democritus
His idea was that every single object was made with atoms. Asl osaid that atoms can't be destroyed or differ in size. -
Joseph Louis Proust
He published the Law of Define Proportions.This law states that a compound is composed of exact proportions of elements by mass regardless of how the compound was created. -
Antonie Lavoisier
Invented the Law of Conversation.The law states that matter cannot be made or destroyed. He also hints at the rearrangement of matter in reactions. Matter rearranged, but never disappeared. -
John Dalton
Proposed an "atomic theory" with sperical solid atoms based upon measurable properties of mass. He came up with three distinct states, elastic fluids, liquids and solids. -
Michael Faraday
Studied the effect of electricity on solutions, which is "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis. -
Henry Becquerel
He discovered radioactivity. -
J.J. Thomson
Created a model called "raisin cake" in which thousands of negatively charged swarm in a massless positive energy cloud. -
Marie & Pierre Curie
They studied uranium and thorium and called their spontaneous decay process "radioactivity". Pierre discovered radioactive elements called polonium and radium. -
Max Planck
He published papers on entropy, on thermoelectricity and on the theroy of dilute solutions. -
Albert Einstein
His famous equation E=mc3 confirmed that atoms can be broken apart. -
Robert Millikan
His earliest success was that determination of a charge carried by an electron using "falling-drop method." -
Ernest Rutherford
Using alpha particles as atomic bullets, he established that the nucleus was very dense, very small and positivly charged -
Niels Bohr
He explained what happens inside an atom and developed a picture of atomic structure. Also he was the first person to discover that electrons travel in sperate orbits. -
Louis DeBrogile
Developed the wave mechanics theory.The theory improved ourknowledge of the physical nature on the atomic scale. -
Edwin Schrondinger
He views electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. -
James Chadwick
Using alpha particles discovered a neutral atomic particle with a mass close to a proton. This is how the nuetron was discovered. -
Otto Hahn and Lisa Meitner
Discovered the splitting of the atomic nucleus with Uranium and Thorium. This became known as Fission. -
Glen T. Seaborg
Synthesized 6 transuranium elements and suggested a change in the layout of the periodic table. -
Aristotle
Didn't believe in atomis theory.He thought of 4 elements fire, earth, water, and air.
