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Antoine Lavoisier
He found that mass is conserved in a chemical reaction. -
Joseph Louis Proust
He was best known for his discovery of the law of constant composition that stated chemical compounds always combine in constant proportions. -
John Dalton
He found that the chemical makeup of air was a mechanical system composed of small individual particles that used pressure applied by each gas independently. -
Michael Faraday
He discovered electromagnetic induction, the principle behind the electric transformer and generator. This discovery was crucial in allowing electricity to be transformed from a curiosity into a powerful new technology. -
Henri Becquerel
He discovered radioactivity, the emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei. -
J.J. Thomson
He discovered the electron during a series of experiments that were made to study the nature of electric discharge in a high-vacuum cathode-ray tube, which was being investigated by many scientists at that time. -
Max Planck
He originated the Quantum Theory, which is a theory of matter and energy based on quanta, a discrete quantity of energy proportional in magnitude to the frequency of the radiation it represents. -
Marie Curie
She was known for making contributions to the study of radium and radiation was an instrumental technology for the future development of the atomic bomb. -
Albert Einstein
He created the quantum theory of light, the idea that light exists as tiny packets, or particles, which he called photons. He also proposed that we live in a quantum universe, one built out of tiny, discrete chunks of energy and matter. -
Robert Milikan
Known for his measurement of the elementary electronic charge and for his work on the photoelectric effect. -
Ernest Rutherford
He discovered the nucleus of the atom. -
Niels Bohr
Discovered that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. -
Louis DeBroglie
His research on quantum theory and for his discovery of wave nature of electrons was a vital part of knowledge of matter during the time period. -
Ernest Schrodinger
He found the probability that an electron can be found in a given region of space at a given time. -
James Chadwick
Discovered the neutron, a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen. -
Lisa Meitner
Conducted experiments verifying that heavy elements capture neutrons and form unstable products which undergo fission. This process ejects more neutrons continuing the fission chain reaction. -
Otto Hahn
He discovered nuclear fission, which is a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy. -
Glen T. Seaborg
He was known for isolating and identifying transuranium elements, those heavier than uranium. Plutonium and Californium were two. -
Sphere model
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Plum Pudding Model
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Planetary Model
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Electron Cloud Model
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Quantum Mechanical Model
