1 / 19

Scientists

Scientists. The atom. Democritus . - 400 BC- Greek philosopher - No experimenting Matter made up of indivisible particles = “ atomos ”. Dalton. 1801: Thomas Jefferson President 1802: John Dalton experimented and concluded…. 1806: Fall of Roman Empire . Dalton.

chione
Download Presentation

Scientists

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Scientists The atom

  2. Democritus - 400 BC- Greek philosopher - No experimenting • Matter made up of indivisible particles = “atomos”

  3. Dalton 1801: Thomas Jefferson President 1802: John Dalton experimented and concluded…. 1806: Fall of Roman Empire

  4. Dalton 1. Matter made up small particles= atoms • Cant be created, destroyed, or made smaller 2. Atoms of same element are identical • Different elements = different atoms 3. Chem. Rxn atoms separate, join, or rearrange 4. Atoms of different elements can combine in whole number ratios: compounds.

  5. 1850’s- Steam • Steam powered engines of ships, trains, & factories • Key Question’s of 19th Century= • “How to build more effective steam engines” and • “ How to predict behavior of steam at high temps and pressures.”

  6. 1896- Uranium - Uranium was found to emit strange energy: - Radioactivity: warm to the touch - Can unlock secrets to the atom

  7. 1898- Marie Curie Concluded Uranium atom gave off radiation ( but another chemist discovered first) Found Radium – led to cancer fighting drugs Won two Nobel Peace Prizes Found Polonium Kept radioactive materials in her pocket Died of leukemia from radioactive materials

  8. 1904-J.J. Thomson • Plum Pudding Model/ Chocolate Chip Cookie • Discovered electrons ( 1897) • Experiment with cathode ray tube • Particles move toward positive end • Particles must be negatively charged • Disproved that the atom was indivisible (could be broken into parts)

  9. Thomson versus Rutherford

  10. Rutherford’s Goldfoil Experiment Result: majority passed straight through some bounced @ large angles & straight back

  11. 1911-Rutherford • Discovered: • atom was mostly empty space • Atom had a dense positively charged center • Disproved the Plum Pudding Model • (he was a grad student of Thomson)

  12. 1913-Bohr • Planetary model of atom • Electrons move in an orbit • Each orbit had a definite energy

  13. 1914- 1918: World War I

  14. 1926- Schrodinger • Extension of Bohr’s model • The electron “cloud” shows where the electron is most likely to be • You have a 90% chance of finding the electron • Electrons move like waves

  15. Quantum Mechanical Model

  16. History of Atomic Models Dalton 1802 Thompson 1904- “plum pudding” Rutherford 1911 Bohr 1913 “planetary model” Quantum mechanical model

  17. 1927- Heisenberg Uncertainty Principle Can not know the speed and the location of the e- at the same time

  18. 1932-Chadwick • Prisoner of war in WW1 • Worked for Rutherford • Discovered neutron • Issue: mass of helium was 4 but it only had 2 protons

  19. Summary Video

More Related