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Antoine Lavoisier
Antoine began the conversation on what an atom was exactly. He also hints at the rearrangement of matter in reactions. Matter rearranged, but never disappeared. -
Joseph Louis Proust
Proust stated the Law of Definite Proportions. The law states that the ratio of elements in a compound is always the same/constant. He also hinted at the 'lego'ness of matter; he believed that matter could be put together in certain patterns to make bigger, different, unique matter -
John Dalton
Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass. Dalton's atomic theory also stated that all compounds were composed of combinations of these atoms in defined ratios. -
Michael Faraday
Faraday studied the effect of electricity on solutions, coined term "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis. Faraday himself was not a proponent of atomism. -
Henri Becquerel
While studying the effect of x-rays on photographic film, he discovered some chemicals spontaneously decompose and give off very pentrating rays. -
J.J.Thomson
Thomson determined that all matter is made up of tiny particles that are much smaller than atoms. He originally called these particles 'corpuscles,' although they are now called electrons. This discovery upended the prevailing theory that the atom was the smallest fundamental unit. -
Marie Curie
Her continued systematic studies of the various chemical compounds gave the surprising result that the strength of the radiation did not depend on the compound that was being studied. It depended only on the amount of uranium or thorium. -
Max Planck
Plank realized that light and other electromagnetic waves were emitted in discrete packets of energy that he called "quanta" - which could only take on certain discrete values (multiples of a certain constant -
Albert Einstein
Produced the equation E=mc 2 -
Robert Milikan
The experiment entailed observing tiny charged droplets of oil between two horizontal metal electrodes. The oil drop experiment was an experiment performed by Robert A. Millikan and Harvey Fletcher in 1909 to measure the elementary electric charge (the charge of the electron). -
Ernest Rutherford
Rutherfords studies showed that when alpha particles are fired into gas atoms, a few are violently deflected, which implies a dense, positively charged central region containing most of the atomic mass. -
Niels Bohr
Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus. The energy of an electron depends on the size of the orbit and is lower for smaller orbits. -
Louis DeBroglie
The notion that matter on the atomic scale might have the properties of a wave was rooted in a proposal Einstein had made 20 years before. Einstein had suggested that light of short wavelengths might under some conditions be observed to behave as if it were composed of particles. -
Ernest Schrodinger
The Electron Cloud model consisted of a dense nucleus surrounded by a cloud of electrons at various levels in orbitals. -
James Chadwick
Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons - elementary particles devoid of any electrical charge. -
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
Hahn discovered the fission of uranium. -
Glen T. Seaborg
Synthesized 6 transuranium elements and suggested a change in the layout of the periodic table.
