P6- Radioactive Materials

Revision cards based on the otes made previously covers the different kinds of radiation, Rutherfords experiment and radioactive decay.

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  • Created by: Katherine
  • Created on: 02-06-13 12:20

Alpha Radiation

  1. Particles are big and slow moving, relativity heavy
  2. Don't penetrate to far into materials
  3. Released by a heavy nuclei i.e. Uranium
  4. A helium nucleus (He) made up of 2 protons and 2 neutrons
  5. Mass of 4 and charge of 2+
  6. Decay always changes the element, as it losses it's protons
  7. Alpha particles get blocked by paper and similar materials
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Beta Radiation

  1. Beta particles move fast ad are quite small
  2. Penetrate moderately  until stopped
  3. Released by a nuclei with too many neutrons
  4. During decay a neutron turns into a proton so the element changes
  5. Beta particles are identical to electrons, virtually no mass and a -1 charge
  6. Beta particles are blocked by thin aluminium and similar materials
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Gamma Radiation

  1. Used to get rid of extra energy after Alpha and Beta radiation
  2. A electromagnetic wave, with no mass
  3. Can penetrate a long way into materials without it being stopped
  4. As it is just energy it doesn't alter the element
  5. Gamma particles are blocked by thick lead
  6. Any other similar materials will also block it
  7. Gamma radiation is used for sterilising surgical instruments and hygiene products
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Rutherford

  1. Atom model dates back to 1910, experimented by Ernest Rutherford
  2. Rutherford designed an experiment with his assistants Hans Geiger and Ernest Marshden
  3. They did this by:
  4. Using gold foil as it rolled out thinly to the thickness of just a few atoms
  5. Directed Alpha radiation at the foil
  6. There should be flashes of light as the radiation strike the material
  7. They worked all night counting the flashes from different angles.
  8. They observed that most of the particles passed straight through the foil
  9. A small fraction of the particles reflected back towards the source
  10. Rutherford released there was a positive charge within the atom
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Radioactive decay

  1. Radioactive Decay>  Spontaneous decay change in an unstable giving out Alpha, Beta and Gamma radiation
  2. In atoms in which the Nucleus is unstable, the atoms decay to become more stable. They emit energetic radiation and there nucleus changes
  3. Radio active decay doesn't affect any physical or chemical change with in the atom
  4. Radioactive Platinum decays to turn into gold (via Beta Radiation)
  5. Every time an unstable nucleus decays and emits radiation, which means that one nucleus is not able to decay later
  6. The more unstable the decay the more the radioactivity decreases
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More

  1. The decreasing of the radiation varies quite a bit
  2. The activity never reaches zero making it hard to measure
  3. Use the half-life to measure how quickly radioactivity decreases
  4. Half-life> Time taken for half of the radioactive nuclei now present to decay
  5. Short half-life means activity falls quickly
  6. Long half-life means the activity falls slowly
  7. Isotopes> atoms of the same element that have different mass numbers because they have different numbers of neurons in the nucleus
  8. Background radiation> the low-level radiation, mostly  natural sources, that everyone is exposed to all the time everywhere.
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