Name:___________________________________ Date:_____________________ Class period:______
(ANSWER KEY)
Unit: Nuclear Chemistry
Test Review
What
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to study?
Quizzes: #1
Homework: worksheets #1-#4
Notes: Properties of Radiation  Applications of Nuclear Chemistry
Bell Ringers: Matching, Half-lives, Writing Transmutations
What will the questions be like? What can I expect?
This test will be just like the previous quizzes you have taken.
 Matching
 Short answer
 Multiple choice
 Calculations
Sample questions/Important Topics
1. Fill in the best answer for each of the following:
a) The transformation of one atom into another atom is called transmutation.
b) Three types of radiation include gamma, beta, and alpha.
c) During radioactive decay, the nucleus will emit particles of radiation in order to become
more stable.
d) The reactions inside the sun is an example of a fusion reaction.
e) If you wanted to block alpha radiation, paper or clothing can be used.
f) Radioactive isotopes, or radioisotopes, have different mass numbers but the same
atomic number and will decay over time.
g) Uranium-238 is used to calculate the date of a specimen that is embedded deep within
the earth.
h) Half-life is the time it takes for half a sample of nuclei to decay into more stable nuclei.
i) Fusion reactions release more energy than fission reactions.
j) For elements that have an atomic number less than 20, stable nuclei have a
neutron:proton ratio equal to 1 (one).
k) Radioactivity is the spontaneous emission of radiation by an unstable nucleus.
l) A common isotope used to diagnose thyroid disease is called Iodine-131.
m) During beta decay, the atomic number will increase by 1 and the mass number will
remain unchanged.
n) Rutherford used alpha particles in his Gold Foil Experiment.
2. How do nuclear chain reactions occur?
Nuclear chain reactions occur during fission reactions where a nucleus is bombarded with
radiation. An extremely unstable nucleus is formed and decays immediately. The radiation
released from the decay will collide with other unreacted nuclei causing the process to
repeat all over again.
3. Why is it important that radioactive isotopes used internally for diagnosis or treatment have
relatively short half-lives?
It is important that these radioisotopes have short half-lives so that the person is not
exposed to harmful radiation for an extended length of time.
4. What happens to an atom with a nucleus that falls outside the band of stability?
The nucleus will undergo radioactive decay into a more stable nucleus.
5. Which isotope is more stable, hydrogen-1 or hydrogen 3? Explain your choice.
It is expected that hydrogen-1 will be more stable because the n:p ratio is equal to 1.
Elements with atomic numbers less than 20 are stable when the number of neutrons equal
the number of protons.
6. If you look a typical nuclear equation, is it possible to tell whether or not the reaction
produces gamma radiation? Why or why not?
It is not possible to tell because the mass number and atomic number are both equal to
zero. Therefore it is not factored into the equation when one is balancing it.
Directions: Show your work for the following calculations.
7. Phosphorus-32 (t1/2 = 14.3days) is used in the treatment of leukemia, among other things.
a) The isotope undergoes beta particle decay. Write a balanced equation for this
process.
32
0
32
P
e
+
S
15
-1
16
b) How many half-lives did the sample go through at the end of 28.6 days?
28.6 days/14.3 days = 2 half lives
c) If you begin with 4.8g of this radioisotope, what mass will remain after 28.6 days?
4.8g x (.5)2 = 1.2 grams
8. Iodine-131 is used to treat and diagnose thyroid cancer. The half-life is 8.04 days.
a) How many half-lives did the sample go through at the end of 40.2 days?
40.2 days/8.04 days = 5 half lives
b) If you begin with 2.4g of this radioisotope, what mass will remain after 28.6 days?
2.4g x (.5)5 = 0.075 grams
9. Copper acetate containing Cu-64 is used to study brain tumors. This isotope has a half-life
of 12.7 hours. If you begin with 0.0025mg, what mass in milligrams remains after two halflives?
0.0025mg x (.5)2 = 6.3x10-4 milligrams
10. Complete and balance the equations for the following nuclear reactions.
27
4
1
30
Al
He
n +
+
13
2
0
15
P
32
S
16
+
1
0
n
1
1
H
+
32
15
96
42
+
2
1
H
1
0
n
+
97
Tc
43
+
4
He
2
Mo
239
Pu
94
240
Am
95
+
1
1
P
+
H
2 10 n
11. Write an equation describing the radioactive decay of each of the following radioisotopes.
The particle produced is shown in parentheses. (Be sure to include all missing information
including symbol, mass number, and atomic number.)
a)
50Ti
b)
210Po
c)
68Ge
(beta)
(alpha)
(positron)
50
22
210
84
Ti
Po
68
Ge
32
0
-1
e
50
23
+
4
He
2
+
206
82
0
e
+1
+
68
31
V
Pb
Ga