Skip to main content
Back

Band of Stability quiz

Control buttons has been changed to "navigation" mode.
1/15

Terms in this set (15)

  • What is the central idea of nuclear chemistry regarding unstable nuclei?
    Unstable nuclei will give off radiation to achieve stability.
  • What role do neutrons play in the nucleus?
    Neutrons act as a glue to hold the positively charged protons together in the nucleus.
  • What are the two major forces acting within the nucleus?
    The attractive strong nuclear force (from neutrons) and the repulsive columbic force (from protons).
  • How does the neutron-to-proton ratio (n/z) relate to nuclear stability?
    The neutron-to-proton ratio helps determine if an isotope is stable or likely to undergo radioactive decay.
  • What is the most stable neutron-to-proton ratio for elements with atomic number ≤ 20?
    The most stable ratio is 1:1 for elements with atomic number 20 or less.
  • What is the most stable neutron-to-proton ratio for elements with atomic numbers between 21 and 40?
    The most stable ratio is about 1.25 for atomic numbers 21 to 40.
  • At what atomic number do stable nuclei no longer exist, and which element is the heaviest with stable isotopes?
    Stable nuclei do not exist above atomic number 83; bismuth (atomic number 83) is the heaviest element with stable isotopes.
  • What is the 'valley of stability' in nuclear chemistry?
    The valley of stability is the region on a graph where isotopes are stable and not likely to undergo radioactive decay.
  • What does it mean if a nucleus is above the valley of stability?
    It has too many neutrons, making the strong nuclear force greater than the repulsive force.
  • What nuclear processes can move a nucleus above the valley of stability toward stability?
    Neutron emission or beta emission (beta decay) can decrease neutrons or increase protons, moving the nucleus toward stability.
  • What does it mean if a nucleus is below the valley of stability?
    It has too many protons, making the repulsive force greater than the strong nuclear force.
  • What nuclear processes can move a nucleus below the valley of stability toward stability?
    Positron emission or electron capture can increase neutrons or decrease protons, moving the nucleus toward stability.
  • What happens to nuclei in the top right corner of the stability graph (atomic mass ≥ 200)?
    They have too many neutrons and protons and may undergo alpha decay or spontaneous fission to become more stable.
  • What is an example of a nucleus undergoing alpha decay to reach stability?
    Uranium-238 can undergo 8 alpha decays and 6 beta emissions to become lead-206.
  • What is spontaneous fission and give an example?
    Spontaneous fission is when a heavy nucleus splits into smaller nuclei; for example, californium-252 can split into technetium-106, cesium-143, neutrons, and gamma emissions.