Test 2 Geology

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  1. Atomic Number:
  2. Mass number
  3. Isotope
  4. Radioactivity
  5. Radioactive isotope
  6. Rate of decay
  7. Half-life
  8. Alpha decay
    The alpha particle is 2 protons + 2 neutrons (= helium nucleus), uranium undergoes alpha decay, and that alpha decay lowers uranium's mass by four and atomic number by 2.
  9. Beta decay
    The beta particle is an electron, that a neutron is transformed into an electron and a proton, that 40K undergoes beta decay to form 40Ca, and that beta decay of potassium increases the atomic number by one but does not change the mass number.
  10. Electron capture
    a proton captures an electron and is transformed into a neutron, that 40K undergoes beta decay to form 40Ar, and that electron capture decay of potassium decreases the atomic number by one but does not change the mass number.
  11. Uranium-thorium-lead system
    235U has a half-life of ~700 million years and 238U has a half-life of ~ 4.4 billion years.

    that both finally decay to different stable isotopes of lead.

    the age of a rock or mineral is determined by measuring the amount of uranium and lead isotopes and then using a formula and the known half-life to calculate age.

    235U will undergo fission and can be used as a nuclear fuel and to make atomic bombs
  12. Carbon-14 age dating
    Carbon-14 has a short half-life (~5730 years)

    Carbon-14 is always being made in the earth's upper atmosphere by a neutron hitting a 14N atom with the neutron being added to the atom.

    As a proton is kicked out forming carbon-14, the carbon-14 decays to nitrogen

    The caron-14 combines with oxygen to form carbon dioxide, which is used by plants during photosynthesis.

    As long as plants and animals are alive they will have a constant amount of carbon-14.

    After death the amount of carbon-14 starts to decline

    The carbon-14 system works well on dying bones, wood, charcoal and other organic materials that are younger than ~50,000 years.
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Test 2 Geology
Test 2 Geology
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