Question | Answer |
Democtritus | 400 BC- atom concept |
George Bauer | 1500s ore |
Philippus Theophrastus Bombastras von Hohenheim | 1500s medicine |
Berzelius | late 1700s (alchemy) symbols for elements |
George Stahl | 1600 phlogiston |
Antoine Lavoisier | 1700 oxygen and LOCOM (conservation of mass) |
Proust | 1700 LODP (def. proportions) |
Dalton | 1800 LOMP (multiple proportions). Atomic theory. |
Thomson | 1900. CRT tubes. Discovered electrons. Determined electron had mass, - charge and in all matter. |
Robert Millikan | 1904. found exact charge & mass of an electron. Electron is 1/1837 of a hydrogen atom. |
Thomson's model | cookie dough, plum pudding. |
Rutherford | alpha particle @ gold foil. Nucleus small, but has all mass. Most of atom = empty space. |
Henri Becquerel | Discovered uranium. 1st to describe radioactivity. |
Marie Curie | discovered Radium and radioactive elements. |
Atomic # | Z (# of protons) |
Atomic Mass # | A (protons and neutrons) |
atomic mass unit | amu |
p+, n*, e- | protons, neutrons, electrons |
mole | 6.022x10^23 |
Avogadro's # | 6.022x10^23 |
nucleon | protons and neutrons |
nuclide | atom; identified by # of protons and neutrons. Ex: 228:88 Ra or Radium-228. |
Ratio of neutrons:protons in low atomic # elements | 1:1 |
Ratio in larger atomic # elements | 1.5:1 |
2, 8, 20, 28, 50, 82, 126 | magic cuz stable combination in dif nuclear shells |
Alpha particle | 2 protons and neutrons bound together (4:2 He) |
Gamma rays released in order to | make nucleus more stable |
Roentgen | 2*10^9 ion pairs passing through 1 cm^3 of dry air. |
Rem | dose of type of ionizing radiation; radiation effect on human tissue. |