Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Name: ____________________________________ HISTORY OF THE ATOMIC MODEL 1800 1950 1900 2000 JOHN DALTON DMITRI MEDELEEV JJ THOMSON ROBERT MILLIKAN ERNEST RUTHERFORD NIELS BOHR (1766-1844) (1834-1907) (1856-1940) (1868-1953) (1871-1937) (1885-1962) Dalton Model of the Atom (Billiard Ball Model) 1803 Atoms are the tiniest particle Atoms of the same element are the same Atoms of different elements are different Atoms cannot be created, destroyed, or divided Periodic Table 1869 Grouped like elements together based on physical properties into 7 groups Placed elements based on atomic mass Discovered properties were a function of atomic mass Predicted missing elements Discovered the electron using cathode ray tubes and an electric field Found the electron to be negatively charged Plum Pudding Model 1897 Oil drop experiment 1908-1917 – atomizer sprayed oil into chamber, falling through a pinhole, atoms are ionized and attracted to the positively or negatively charged plate By varying the charge, an equation could be used to determine the charge of the electron. Built on JJ Thomson’s Plum Pudding Model to create Rutherford’s Model 1910 Gold Foil Experiment Discovered that atoms are mostly empty space - a positive nucleus with a large electron cloud Applied quantum theory to Rutherford’s atom and determined that electrons travel in discrete (quantized) orbits or energy levels or shells Discovered that the emission of light occurs when electrons move from a higher orbital to a lower one Developed the Bohr Model 1920 Name: ____________________________________ HISTORY OF THE ATOMIC MODEL 1800 1950 1900 2000 ERWIN SCHRODINGER JAMES CHADWICK LISE MIETNER MARIA GOEPPART-MAYER MURRAY GELL-MANN (1887-1961) (1891-1974) (1878-1968) (1906-1972) (1929-current) The Schrodinger wave equation Theorized that electrons move like waves Replaced Bohr’s well defined orbits with probability “clouds” Electron Cloud Model 1926 Proved the existence of neutrons (neutral particles with mass located in the nucleus) 1932 Neutrons make up ~ ½ the mass of an atom Discovered the process of nuclear fission 1939 through the theory of Bohr’s “liquid drop” model Discovered the nuclear “Magic Numbers” – the specific ratio of protons and neutrons that enable an atom to be stable 1948 These magic numbers also correlate to a full outer shell of electrons Helped to explain the idea of isotopes 2nd women to win a Nobel Prize Discovered quarks which make up protons and neutrons 1961 Proposed a new quantum property of particles called “the strangeness number”