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Nuclear Energy and Radioactivity

Nuclear Energy and Radioactivity. Environmental Science. Radioactivity:. The spontaneous emission of radiation Created by unstable nuclei of very heavy elements Radioactive elements can give off 3 types of radiation: Alpha: helium nuclei can usually be stopped by a piece of paper

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Nuclear Energy and Radioactivity

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  1. Nuclear Energy and Radioactivity Environmental Science

  2. Radioactivity: • The spontaneous emission of radiation • Created by unstable nuclei of very heavy elements • Radioactive elements can give off 3 types of radiation: • Alpha: • helium nuclei • can usually be stopped by a piece of paper • Beta: • e- which are much smaller and lighter than alpha particles • More penetrating power than alpha particles • Can be stopped by a thick wooden board • Gamma • Extremem energetic form of light • VERY powerful • Several inches of lead of several feet of concrete necessary to stop them

  3. Nuclear Notation: • Atomic Number: • is the number of protons in the nucleus • The Lithium atom has three electrons occupying 2 energy levels and three protons giving it an atomic number Z = 3 . • Atomic Mass: • is the number of particles in the nucleus. • The Lithium nucleus includes four neutrons and 3 protons making up its seven particles and thus a mass number A = 7 • Atomic Structure: • Lithium-7 or 7Li • The mass number isplacedafter the name of the element or is indicated as a superscript preceding the chemical symbol. • 7Li3 • The symbol may also indicate the full atomic structure by adding a subscript representing the atomic number.  

  4. Nuclear Notation Problems • Write the nuclear notation for the following: • Li • U • Pb

  5. Nuclear Decay • Uranium-238 decays to form Thorium-234, a radioactive silvery metal, with the emission of one Helium atom. Thus 238U92    ⇒    234Th90    +    4He2 • The daughter nuclide (thorium-234) has 2 fewer protons and neutrons than the parent nuclide (uranium-238)

  6. Half Life: • A radioactive elements distinctive rate of decay • The amount of time it takes ½ of radioactive material to decompose

  7. Half Life Example Problem • A radioactive isotope has a half-life of 12.4 hours. If a lab starts with a 13.2 mg sample how much will remain after 37.2 hours? • 13.2/2 /2 /2 = 1.65 mg • A radioactive substance has a half-life of 10 years. How much is left after 30 years? • ½ of ½ of ½ or 1/8

  8. Nuclear Radiation Lab pp. 427-429 Procedure and Questions 1&2 Monday April 18

  9. Nuclear Energy Quiz Wednesday April 20

  10. Nuclear Fission • The fission process take place when the nucleus of a heavy atom, like uranium or plutonium, is split in two when struck by a neutron. • The "fissioning" of the nucleus releases two or three new neutrons.

  11. A Fission Equation: 10n + 23592U  13250Sn + 10142Mo + 310n 1 neutron bombards 1 heavy element and it disintegrates into 2 smaller nuclei and 2-3 neutrons

  12. Nuclear Fusion

  13. A Fusion Equation 411H + 20-1e  42He

  14. Using Radioactive Isotopes Labpp. 430-432 All Group Analysis Questions Wednesday April 20

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