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100
Work cited
http://en.wikipedia.org/wiki/Rutherford_model
http://www.rsc.org/chemsoc/timeline/pages/1913.html
http://the-history-of-the-atom.wikispaces.com/Democritus
http://hermesgarpesimanullang.blogspot.com/2013/01/teori-atom-john-dalton-jj-thomson.html
https://sites.google.com/site/chemprojectpdoa/werner-heisenburg
http://www.xtimeline.com/evt/view.aspx?id=652552
http://www.nobelprize.org/educational/physics/quantised_world/structure-1.html
http://www.xtimeline.com/evt/view.aspx?id=962495 -
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Work cited 2
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460
Democritus
His theory: Matter could not be divided into smaller and smaller pieces forever, eventually the smallest possible piece would be obtained. This piece would be indivisible. He named the smallest piece of matter “atomos,” meaning “not to be cut.” To Democritus, atoms were small, hard particles that were all made of the same material, but were different shapes and sizes. Atoms were infinite in number, always moving and capable of joining together. -
John Dalton
He discovered that certain gases only could be combined in certain proportions even if two different compounds shared the same common element or group of elements. Dalton was the first to prepare a table of relative atomic weights. This theory which Dalton first advanced in 1803, is the cornerstone of modern physical science. Dalton's atomic theory rests on the following ideas:
1.All matter consists of tiny particles
2.Atoms are indestructible and unchangeable
3.Elements are characterize -
Eugen Goldstein
He is sometimes called the discoverer of protons. He did experiments with cathode ray tubes, which knock electrons off atoms and attract them to a positively-charged electrode (the cathode). He noticed that a second stream of particles was attracted to the negatively-charged electrode (the anode), so he called them anode rays. However, it was left to one of his students to discover that these rays were sometimes pure protons. -
J.J Thomson
British physicist Joseph John (J. J.) Thomson discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube, an area being investigated by numerous scientists at the time. -
Robert Milikan
Experimenting with cathode rays in 1897, Millikan and J.J. Thomson had discovered negatively charged 'corpuscles', as he called them, with a charge to mass ratio 1840 times that of a hydrogen ion. -
Hantaro Nagaoka
Nagaoka developed a planetary model of the atom. The model was based around an analogy to the explanation of the stability of the Saturn rings (the rings are stable because the planet they orbit is very, very massive) -
Ernest Rutherford
The 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, negative constituents, called electrons, circulate at some distance, much like planets revolving around the Sun. The Rutherford atomic model has been alternatively called the nuclear atom, or the planetary model of the atom. -
Albert Einstein
Instead of just theorizing that atoms may possibly exist, he actually found a way to prove that they did. He did this by using his theories in quantum physics to explain the photoelectric effect and Brownian motion, which ultimately led to solid evidence that atoms exist and even showed how atoms are structured. -
Niels Bohr
Bohr 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.
The chemical element bohrium (Bh), No. 107 on the Periodic Table of the Elements, is named for him. -
Louis De Broglie
He proposed in 1924 that electrons could behave as waves under some conditions, a finding that helped scientists understand that the atom didn't behave like the solar system because electrons do not move in regular orbits. -
Wolfgang Pauli
He is most famous for his "Pauli exclusion principle," which states that no two electrons in an atom can have the same four quantum numbers. For his work in this area he was awarded the 1945 Nobel Prize for physics. -
Erwin Schrodinger
Erwin Schrodinger used mathematical equations to describe the likelihood of finding an electron in a certain position in atomic theory. This atomic model is known as the quantum mechanical model of the atom. This atomic theory predicts the odds of the location of the electron. -
James Chadwick
English physicist who was awarded the 1935 Nobel Prize in physics for his discovery of the neutron in 1932. He was the head of the British scientists who worked on the Manhattan Project during World War II. He was knighted in 1945 for achievements in physics. -
Richard Feynman
American theoretical physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics. -
Max Born
German-British physicist and mathematician who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics and supervised the work of a number of notable physicists in the 1920s and 30s. -
Werner Heisneberg
Werner Heisenberg contributed to the atomic theory by including quantum mechanics, the branch of mechanics, based on quantum theory, used for interpretating the behavior of elementary particles and atoms. -
Ludwig Boltzmann
Austrian physicist and philosopher whose greatest achievement was in the development of statistical mechanics, which explains and predicts how the properties of atoms (such as mass, charge, and structure) determine the physical properties of matter (such as viscosity, thermal conductivity, and diffusion).
