1. A brief presentation on the history of the atom

2. 1800 Dalton: “Matter indeed, seems to consist of elementary lumpy particles” 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

3. 1897 J.J. Thomson: Discovered the electron and proposed a model for the structure of the atom: “Rasin in the pudding” He knew that e - had negative charge 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

4. 1900 Max Planck: When you vibrate atoms strong enough, you can measure the energy only in discrete units (quanta). 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

5. 1905 Albert Einstein: Light absorption can release e - from atoms. “The Photoelectric effect” (Nobel Prize 1921) 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

6. 1911 Ernest Rutherford: Bombarded atoms with α ++. He came up with a new theory about the structure od the atom: “Solar System” like Problems: Loss of energy, continuous spectrum expercted. 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

7. 1912 Niels Bohr: Introduced “Rules” 1. Allowed Orbits 2. Jump from Higher Energy orbit to Lower Energy orbit results to energy emission. 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

8. 1920 Bohr – Sommerfeld: Expanded the initial rules: Orbits of different shapes (Quantum Numbers) 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

9. 1924 Wolfgang – Pauli: Electron spin, “Pauli’s exclusion principle” 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

10. 1926 Erwin Schrodinger: “Why not try to form a model for particle- waves” 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

11. 1927 Werner Heisenberg: “Heisenberg’s uncertainty principle” 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

12. James Chadwik: Discovery of the neutron Carl Anderson: Discovered the positron, which Dirac had predicted in 1928 but was rejected at first Heisenberg: Particles exchange photons 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

13. 1935 Hideki Yukawa: Exchange particles for strong force 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

14. 1940 Feynman, Schwinger: Four known forces, particles 18001897 1900 1905 1911 1912 1920 1924 19261927193519401932

15. Source http://www.nobeliefs.com/atom.htm Compiled by Jim Walker Presentation made by: Tsourlidaki Eleftheria