uranium 238 decay series

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					Name: Jennifer Miyashiro
Topic: Uranium-238 Decay Series
Grade Level: 10 – 12
Course: Chemistry in the Community
Target Class Size: 25 - 30
Objective:
       The students will construct a graph that demonstrates the decay of Uranium-238.
Materials:
        Cards for each of the major decay products
        Blank graph on which to plot decay series
        Periodic table of the elements

Assessment: Accuracy of plotted decay series and answers to questions.


            Procedure: Students will:
               1. Fill in the missing information on the decay
                  product cards.
               2. Fill in the x-axis and y-axis labels on the blank
                  worksheet.                                             214             210          218
                                                                          84
                                                                            Po            84
                                                                                            Po         84
                                                                                                         Po
               3. Cut out the cards.                                        1.6x10-4 s     138 d        3 min
               4. Place the cards in the correct square (based
                  on mass number and atomic number).
               5. Draw an arrow that connects each decay
                                                                         206             210          214
                  product to the one that it will decay into.
                                                                          82
                                                                            Pb            82
                                                                                            Pb         82
                                                                                                         Pb
               6. Next to each arrow, label if it would undergo             Stable         19.4 y       27 min
                  alpha-decay or beta-decay to get to the next
                  product in the decay series.
               7. Check work over carefully.
                                                                         234             230          210
               8. Glue the cards down.
                                                                          90
                                                                            Th            90
                                                                                            Th         83
                                                                                                         Bi
               9. Answer the questions.                                     24 d           8x104 y      5d



                                                                         238             234          234
                                                                          92
                                                                            U             92
                                                                                            U          91
                                                                                                         Pa
                                                                            4.5x109y       2.5x105y     1.17 min



                                                                         214             226          222
                                                                          83
                                                                            Bi            88
                                                                                            Ra         86
                                                                                                         Rn
                                                                            19.7 min       1620 y       3.8 d
                                         URANIUM – 238 DECAY SERIES ACTIVITY

Directions:
Below is a set of cards. Each card contains a major product of the uranium – 238 decay series.
   1. Fill in the missing information on the decay product cards (You will need your periodic table).
   2. Color each of the elements a unique color (hint: you will need 8 colors).
   3. Cut the cards out.
   4. Place the cards in the correct square (based on mass number and atomic number).
   5. Check your work over carefully.
   6. Glue the cards down.
   7. Draw an arrow that connects each decay product to the one that it will decay into. This will take a little thought
       (make sure that the nuclear equations for alpha and beta decay would be balanced).
   8. Next to each arrow, label if the isotope undergoes alpha-decay or beta-decay to get to the next isotope in the
       decay series.
   9. Color the alpha – decay arrows a unique color.
   10. Color the beta – decay arrows a unique color.
   11. Answer the questions.

                                 Each card is supposed to contain the following information:

                                                Mass Number
                                              Atomic Number
                                                           Chemical        Symbol
                                                                             Half - Life


                                                         210                 218
                                        214                 Po                84
                                                  -4
                                         84 1.6x10 s              138 d               3 min

                                        206              210                 214
                                         82                 Pb                82
                                                Stable           19.4 y              27 min

                                        234              230                 210
                                           Th             90                  83
                                                  24 d           8x104 y                5d

                                        238              234                 234
                                         92                 U                 91
                                           4.5x109y         2.5x105y               1.17 min

                                        214              226                 222
                                         83                 Ra                  Rn
                                              19.7 min           1620 y               3.8 d
Questions:

   1. What are the first and last isotopes in the decay series?


   2. Which isotope has the longest half – life? How long is it?


   3. Which isotope has the shortest half – life? How long is it?


   4. Fill in the following table for radon – 222.
                                          Time Elapsed         % of Rn – 222 remaining
                                               0 days                     100




   5. Approximately, what is the sum of allof the half – lives in this decay series?



   6. Which of these isotopes would give off the most amount of radiation in a short period of time? Explain your
      reasoning.



   7. Generally, a radioactive isotope is considered “safe” after ten half – lives. How long is that time period for U – 238?
     Name: _________________________________________     Date: _________________   Period: ________

                                         URANIUM – 238 DECAY SERIES

                92


                91


                90


                89


                88
ATOMIC NUMBER




                87


                86


                85


                84


                83


                82


                81

                     206   210     214         218      222       226       230       234        238

                                                MASS NUMBER

				
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posted:12/2/2011
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