1.    The number of protons and neutrons determine variations in physical properties              
                     of elements observed in isotopes. Naturally radioactive elements decay
                     spontaneously. X-rays can be produced when metallic anodes are bombarded
                     with electrons in a cathode ray tube. (Nuclear Chemistry topics may be included
                     with the study of Atomic Structure.) The discovery of fundamental particles may
                     be used to develop the atomic model. Radioactive decay and half-life may be used
                     in kinetics to illustrate first-order rate reactions (see Rates of Reactions module).
              2.    Tritium is a naturally occurring radioactive isotope of hydrogen. It has two
                     neutrons and one proton in its nucleus, exists in the diatomic state, and
                     constitutes a very small percentage of the hydrogen content of water. Since
                     it has a half-life of 12.3 years, it can be used for dating rather ãyoungä
                     samples. For example, after a wine is bottled, it becomes a closed system; it
                     can no longer exchange substances with the outside world, and its tritium
                     content will decay at the rate dictated by its half-life. Meanwhile, the
                     naturally occurring level of tritium worldwide remains relatively constant.
                     The tritium level of the wine can be compared to that of ordinary water to
                    determine the wineâs age. For example, if a port wine is tested for tritium
                    content along with ordinary water, and it is found that its tritium level is only
                    30.6% of that of the tritium activity of water, then one can infer that the wine
                    is 21 years old.
                   Nuclear physicists concentrate on the study and expansion of knowledge of                       
                   subatomic particles, their structure, and models for the nuclear atom.
                   Therefore, nuclear chemistry is an area with strong overlap with a general
                   physics course. Radioactivity, fission, fusion, and nuclear reactors are also
                   important areas to the nonscientist.
 

      Community                                                                                                                                  
      Field trips to: nearby nuclear power plant; nuclear medicine center at most large hospitals.

      Societal
          1.    Americium (Am) is the ionizing source in smoke detectors.
          2.    Nuclear medicine.
          3.    Carbon-14 is used to date objects made of wood or other formerly living material.
                 Examples include the Shroud of Turin, Native American artifacts, bones, etc.
          4.    The current clamor over radon gas risks in well-insulated homes built over
                 uranium-rich bedrock.
          5.    Camping lanterns have a mantle containing some radioactive thorium.
          6.    At one time, watch dials were painted with a paint containing radium in order
                 to make them glow in the dark. The radium was harmful to the health of the
                 factory workers÷in particular the women who hand-painted the dials,
                 frequently licking their small paint brushes. Now, tritium (³H) is used, but due
                 to its much shorter half-life, the face may visibly dim during the life of the watch.
          7.    Some EXIT signs are illuminated by tritium rather than by electricity. Can
                 you think why this is an advantage? [In a power failure, an electrically
                 powered EXIT sign would not remain lighted.]
 
 

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