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Nuclear Chemistry

Nuclear Chemistry. Radioactivity : Definition : occurs when the nucleus of an unstable atom emits ionizing radiation Radiation- the movement of energy by particles or waves Electromagnetic radiation. Non-ionizing Radiation- low energy; usually not harmful

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Nuclear Chemistry

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  1. Nuclear Chemistry

  2. Radioactivity: • Definition: occurs when the nucleus of an unstable atom emits ionizing radiation • Radiation- the movement of energy by particles or waves • Electromagnetic radiation

  3. Non-ionizing Radiation- low energy; usually not harmful • Ionizing Radiation- carry enough energy to “ionize” atoms • Elements after atomic number 83 are radioactive

  4. Isotope – • Radioisotope-

  5. Nuclear Reactions • Involve a change in the atom’s nucleus (protons and neutrons) • Types: • Fission • Fusion

  6. Types of Radiation • Alpha α (Alpha Decay) • Alpha particle = 2p+ and 2n0 • U  Th + He + 2 + ϒ • Alpha particle is a He nucleus • ϒ accounts for energy lost during reaction • In the reaction, we must conserve p+ and n0 • Don’t penetrate too far, but can cause skin problems • Sources have a long half-life (around for a long time) • Discovered by Rutherford and his students (Geiger)

  7. Types of Radiation • Beta ϐ (Beta Decay) • Beta particle: fast moving electron (-1 charge) • ϐ or e • Formed when a neutron is split into a proton and a ϐ particle (electron) • n  p + ϐ + ϒ • There is no change in the mass #, only in atomic # • Atomic # changes because the e- emitted during ϐrxn (ϐ decay) has been removed from a neutron (charge of 0) leaving behind a proton • Rb Sr + e- • Damaging to skin because they can travel through a few inches of tissue

  8. Types of Radiation • Gamma Rays • Gamma Rays: high energy radiation (electromagnetic) that is massless • No electrical charge • Often accompany α and ϐ reactions • Harmful- can deeply penetrate skin

  9. http://www.bcm.edu/bodycomplab/Radprimer/radpenetration.htm

  10. Electromagnetic Spectrum

  11. Practice Equations:

  12. Radiation Exposure • Accumulated Doses • Measured in units called rem: measures doses of radiation while accounting for energy of radiation, type of living tissue absorbing radiation and time of exposure. • Background radiation- Where does this it come from?

  13. Radiation Exposure • How do we detect radiation? • Geiger Counter • Tube filled with gas that absorbs radiation and becomes ionized  charge  current  measure the amount of radiation

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