-
400
Democritus
400 BC --- Found that not all atoms are the same; always moving. Indivisible, Solid Sphere Model: said all matter is composed of indivisible tiny things that can't be seen by the naked eye. http://www.mlquotes.com/authors/democritus/ -
400
Solid Sphere Model
400 BC ish. Said all matter is composed of indivisible tiny things that can't be seen by the naked eye. http://www.glogster.com/xavner1/history-of-the-atom/g-6l8sj6bhftol45omkhllqa0 -
John Dalton
Made an atomic theory. His findings became the base of Dalton's Atomic Laws/Model. 1.) Pure elements consists of atoms 2.) Atoms of an element are all the same for that element 3.) Atoms of different elements can be told apart from their atomic weights 4.) Atoms of elements combine to form chemical compounds 5.) Atoms can not be created or destroyed in a chemical reaction. http://en.wikipedia.org/wiki/John_Dalton -
J.J. Thomson
Found electrons and subatomic particles when working with cathode ray tubes. Was working with glass tubes and electricity and messed up and discovered electrons. Founded the Plum Pudding Model. http://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/atomic-and-nuclear-structure/thomson.aspx -
Plum Pudding Model
Said the atom was a sphere of positive electricity (red), with negative particles (blue) throughout. Came right after the discovery of the electron. Made by JJ Thomson http://www.gcsescience.com/prad34-plumb-pudding.htm -
Albert Einstein
Said that light consists of quanta, bundles of energy which behave somewhat like particles. Formulated the Special Theory of Relativity. http://fineartamerica.com/art/all/albert+einstein/framed+prints -
Robert Millikan
Wanted to find electric charge of electrons. Had an experiment where he measured oil droplets where it proved electrons were negatively charged. http://en.wikipedia.org/wiki/Robert_Andrews_Millikan -
Ernest Rutherford
Discovered the atomic nucleus using others' research. Used a thin foil made of gold medal to find positive and negative charges in an atom. http://www.biography.com/people/ernest-rutherford-39099 -
Neils Bohr
Found the structure of the atom and their radiations. Discovered the Principle of Complementary. Started the basis of the quantum theory. http://www.nbi.ku.dk/english/www/niels/ -
Planetary Model
Rutherford and Bohr contributed to this model. Rutherford said the atom is mostly empty space with a nucleus with a positve charge (red) surrounded by negative electrons (small blue circles). Bohr said that they circulate the atom. http://timelineanyaandregina.wikispaces.com/ http://timelineanyaandregina.wikispaces.com/ -
Louis de Broglie
Received Nobel Prize for physics. Believed that elecrons can act like both particles and waves. Said the waves produced by the electrons contained in the orbit around the nucleus, set up a standing wave of certain energy, frequency, and wavelength. http://www.nobelprize.org/nobel_prizes/physics/laureates/1929/ -
Werner Heisenberg
Discovered electron cloud model with Schrodinger. Said atoms consisted of dense nuclei, with many protons and neutrons and surrounded with electrons. Said they all have different energy levels and charges. http://fixquotes.com/authors/werner-heisenberg.htm -
Wolfgang Pauli
Altered Bohr's model of the atom. Introduced two new quantum numbers. Founded the Pauli Principle (stating that any 2 electons can't have identical sets of quantum numbers. Said that protons/neutrons in the nucleus were given quantum numbers; it also applies to the nucleus. http://en.wikipedia.org/wiki/Wolfgang_Pauli -
Erwin Schrodinger
Discovered electron cloud with Heisenberg. Contributed to wave mechanics and quantum mechanics. https://pscpperiod6mm.wikispaces.com/Erwin+Schrodinger -
James Chadwick
Discovered the neutron. Found there is no charge in a neutron. http://en.wikipedia.org/wiki/James_Chadwick -
Modern Model
Electrons are in constant motion around the nucleus, protons and neutrons jiggle within the nucleus, and quarks jiggle within the protons and neutrons. http://linoit.com/users/bratenjr/canvases/a -
Nuclear Model
Has a nucleus of protons (+) and neutrons (neutral) with electrons (-) circulating the nucleus. -
The Origin of the Atomic Theory
Founded by Democritus.
