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370
Democratis
Firsr Atomic Theory in 370 BC -
Antoine Lavoisier
He was also the first to establish that sulfur was an element rather than a compound. -
Law of Conservation of Mass
The law of conservation of mass, also known as the principle of mass/matter conservation, states that the mass of an isolated system will remain constant over time. -
John Dalton
Best know for his pioneering work in the development of modern atomic theory, and his research into colour blindess. -
Cathode Ray Tube
They were first observed in 1869 by German physicist Johann Hittorf -
Plum Pudding Atomic Model
The plum pudding model of the atom by J. J. Thomson, who discovered the electron in 1897, was proposed in 1904 before the discovery of the atomic nucleus in order to add the electron to the atomic model. -
J.J. Thomson
Thomson was awarded the 1906 Nobel Prize in Physics for the discovery of the electron and for his work on the conduction of electricity in gases. -
Dmitri Medeleev
Credited as being the creator of the first version of the periodic table of elements. -
Gold Foil Experiment
Experiment conducted to probe the structure of the atom. -
Rutherford Model
Contained the new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and with this central volume also containing the bulk of the atomic mass of the atom. -
Bohr Planetary Model
In atomic physics, the Bohr model, introduced by Niels Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with electrostatic forces providing attraction, rather than gravity. -
Henry Moseley
Outstanding contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number. -
Dalton's Atmoc Theory
Theory of the nature of matter, which states that matter is composed of discrete units called atoms, as opposed to the obsolete notion that matter could be divided into any arbitrarily small quantity. Date: 19th century. -
Quantum Mechanical Model
Electrons are defined as standing waves. The electron probability distribution gives the areas in which the probability of electron presence is high. -
Electron Cloud Model
Atom model wherein electrons are no longer depicted as particles moving around the nucleus in a fixed orbit. -
Ernest Rutherford
Discovered the concept of radioactive half-life, proved that radioactivity involved the transmutation of one chemical element to another. -
James Chadwick
English Nobel laureate in physics awarded for his discovery of the neutron. -
Robert Millikan
American experimental physicist, and Nobel laureate in physics for his measurement of the charge on the electron and for his work on the photoelectric effect. -
Erwin Schrodinger
Austrian physicist who developed a number of fundamental results in the field of quantum theory, which formed the basis of wave mechanics -
Niels Bohr
Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics,
