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Joseph Louis Proust
Stated the Law of Definite Proportions which said that the ratio of elements in a compound are always the same / constant. Believed that matter could be put together in certain patterns to make bigger, different, unique matter. -
John Dalton
Proposed that all matter is made of atoms and atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. -
Louis DeBroglie
Believed that electrons can act like both particles and waves, just like light. Waves produced by electrons contained in the orbit around the nucleus set up a standing wave of a certain energy, frequency, and wavelength. -
Michael Faraday
Studied the effect of electricity on solutions and coined the term "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis. -
Henri Becquerel
Discovered one type of radioactivity beta particles which is due to high speed electrons leaving the nucleus of the atom. -
Ernest Rutherford
Postulated the nuclear structure of the atom. His model described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the light, called electrons, circulate at some distance. -
Otto Hahn
Discovered protactinium. Collaborated with Meitner and Fritz Strassman on the process if irradiating uranium and thorium with neutrons. -
Niels Bohr
Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. He was the first to discover 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. -
Marie Curie
Studied uranium and thorium and called their spontaneous decay process "radioactivity". She and her husband Pierre discovered the radioactive elements polonium and radium. -
Max Planck
Used the idea of quanta (discrete units of energy) to explain hot glowing matter. -
J.J Thompson
He suggested the model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. -
Albert Einstein
Published e=mc2. -
Glen T. Seaborg
He and his colleagues are responsible for the identification of more than 100 isotopes of elements throughout the periodic table. He discovered plutonium. -
Robert Millikan
He attempted to measure the charge of an electron. To do this, he used the oil drop experiment, -
Ernest Shrodinger
Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. -
James Chadwick
He discovered the neutron. Predicted the atom would have a neutron. Established that the atomic number is determined by the number of protons in an atom. -
Lisa Meitner
Heavy elements capture neutrons and from unstable products which undergo fission. This process ejects more neutrons continuing the fission chain reaction.
