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Democritus
His hypothesis was made in 456 B.C. Democritus stated, "The universe is composed of two elements: the atoms and the void in which they exist and move."
He also hypothesized that atoms can't be destroyed and believed that there are an infinite amount. -
Robert Boyle
Boyle contributed to the organization of atoms and he was called the Father of Chemistry for his extensive work on materials. He is know for his work on studying gases and having Boyle's Law. He proposed that elements are composed of atoms of various types and sizes that are able to organize themsleves into groups that represent the different chemical substances. -
Antoine Lavoiser
he found that mass is conserved in a chemical reaction. His results led to the law of conservation, which is when matter is conserved in a chemical reaction. The understanding of why matter is conserved is because atoms are neither created or destroyed in a chemical reaction. He also published a list of elements which Boyle added too. Lavoiser started the conversation of what an atom actually was. -
John Dalton
In the 1800's Dalton was the first scientist to explain the behavior of atoms in terms of the measurment of weight. He was also credited with pioneering modern atomic theory, which was 1. all matter is made of atoms, 2. atoms are indivisible and idestructible, 3. compounds are formed by a combination of two or more different kinds of atoms. -
Dmitri Mendeleev
He is known for his work on the periodic table, from arranging 63 of the elements in ascending order of atomoic mass. He also pointed out accepted atomic weihts that was were in error. -
Eugen Goldstein
Goldstein concluded that electrons trabel from negative charged cathode to the postive charged anode. There is also another ray that travels in the opposite direction and they pass through canal rays. -
J.J Thomson
He discovered the electron in a series, a negatively charged subatomic particle, of experiments designed to study the nature of electric discharge in a high-vacuum cathode ray tube. In 1904 he suggested a model of the atom as a sphere of positive matter in which electrons are posittioned by electrostatic forces. -
Ernest Rutherford
Rutherford used cathode rays to bombard atoms with many elemtns which showed that the inner structures correspond with groups of lines that characteriae the elements. Each element would then have an atomic number. -
Henry Moseley
Moseley sorted the elements on the periodic table in order of their atomic numbers. He also discovered a systematic relation between wavelenth and their atomic number. (Moseley's law) -
Max Planck
Planck studied the promblems of radiation processess and the problems with the distribution of energy. -
Niels Bohr
In 1913, he proposed a theory for the hydrogen atom based on quatum theory that energy is transfered only in certain well defined quantities. His theory could explain why atoms emitted light in fixed wavelenghts. -
Robert Millikan
Robert studied the determination of the charge that is carried on the electro by a "falling drop" method. This ended up being constand for all electrons proving the theory of electricity. -
Erwin schrodinger
Erwin believed that atomic spectra should be decided by a kinda of eigehvalue problem. He also sudied and wrote about the problem of unifying gravity and electromagnetism. -
Jame Chadwick
In 1932, he was able to show that in the reaction, a neutral particle with a mass about that of a proton, was emitted. He discovered the particle and named it neutron.
Fun fact: The show Jimmy Neutron is a refrence to James Chadwick discovering the Neutron.
