1 / 11

Evidence For The Atomic Structure

Evidence For The Atomic Structure. Noadswood Science, 2012. Evidence For The Atomic Structure. To understand the Rutherford scattering experiment. Plum Pudding. An early model about the structure of the atom was called the plum pudding model

joseph-head
Download Presentation

Evidence For The Atomic Structure

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. Evidence For The Atomic Structure Noadswood Science, 2012

  2. Evidence For The Atomic Structure • To understand the Rutherford scattering experiment

  3. Plum Pudding • An early model about the structure of the atom was called the plum pudding model • In this model, the atom was imagined to be a sphere of positive charge with negatively charged electrons dotted around inside it like plums in a pudding • The positively charged matter in the atom was evenly spread about (pudding) • The electrons were buried inside (plums)

  4. Disproved • Rutherford, the father of nuclear physics, conducted an experiment which proved the plum pudding idea was incorrect • Rutherford, along with Geiger and Marsden proved the plum pudding model incorrect with their scattering experiment

  5. Scattering Experiment • A beam of alpha particles was aimed at very thin gold foil and their passage through the foil detected

  6. Scattering Experiment • A beam of alpha particles was aimed at very thin gold foil and their passage through the foil detected • The alpha particles were expected to pass straight through the foil, but instead some of the alpha particles emerged from the foil at different angles, and some even came straight back • The positively charged alpha particles were being repelled and deflected by a tiny concentration of positive charge in the atom • As a result of this experiment, the plum pudding model was replaced by the nuclear model of the atom

  7. Scattering Experiment

  8. Scattering Experiment • Most of the alpha particles passed straight through the metal foil • The number of alpha particles deflected per minute decreased as the angle of deflection increased • About 1 in 10’000 alpha particles were deflected by more than 90o • Rutherford said this was like “firing naval shells at cardboard, and discovering the occasional shell rebounds”

  9. Scattering Experiment • From this experiment Rutherford concluded that there is a nucleus at the centre of every atom which: - • Is positively charged because it repels alpha particles • Is much smaller than the atom as most alpha particles passed through it • Is where most of the mass of the atom is located • The nucleus diameter was found to be about 100’000 times smaller than the atom

  10. Scattering Experiment Thin gold foil Alpha particles Most particles passed through, but 1/10’000 were deflected by more than 900

  11. Atomic Structure Electron – negative; mass of 1/2000th Neutron – neutral; mass of 1 Proton – positive; mass of 1

More Related