Name:
Period:
Date:
Unit 4 Nuclear Chemistry Review Study Guide
1. Define the following terms below.
a) Half-life- the length of time during which half of a given number of atoms of a
radioactive nuclide decay
b) Nuclear Fission- the process in which lightweight nuclei combine to form heavier,
more stable nuclei
c) Nuclear Fusion- process in which a very heavy nucleus splits to form medium-weight nuclei
2. Describe the main reason/cause that makes an atom become unstable/radioactive.
If the numbers of protons and neutrons differ from each other by much the atom becomes unstable.
3. Name the 3 types of particles and wave discussed and used in writing nuclear reactions; give the nuclear
symbol for each particle in the table below.
Type/Name
Symbol
1.
alpha
2.
beta
3.
gamma
4. All plants and animals are exposed to background radiation on a daily basis originating from the
environment. Where does the radiation come from? List at least 3 sources.
1. space
2. radioactive carbon in carbon dioxide
3. water, food
5. Do nuclear power plants use nuclear fusion or fission to produce power?
fission
6. Does the sun use nuclear fusion or fission to generate energy? fusion
7. Which elements on the periodic table are radioactive? #84 -on
Complete the following Nuclear Reaction and Half-life problems in the spaces provided.
8. Write a complete nuclear equation when the given nuclide undergoes beta decay.
(Write the beta particle first and let it help you figure out the missing particle.)
a)
255
Es →
+
99
b)
240
93
Np →
+
9. Write a complete nuclear equation when the given nuclide undergoes alpha decay.
(Write the beta particle first and let it help you figure out the missing particle.)
a) 188 W
74
→
+
Name:
Period:
b)
210
Bi
→
Date:
+
83
10. Determine the missing particle, element, or mass and atomic number from the following information.
a)
122
b)
199
Pt
_78_
c)
Sn 
_50____
118
48
+
Cd

+

140
56
199
77
+
Ba
Ir
0
-1
e
11. A radioactive nuclide having a mass of 60g decayed for 4 half-lives. Calculate the mass of nuclide
remaining after the decay period.
60 g →30g →15g→7.5 g→3.75 g Each arrow = 1 ½ life
Answer: 4 half lives
12. What is the mass of the original sample with a t1/2 of 15days that had 8g remaining after decaying for
60days?
How many half lives are in 60 days? 60/15 =4 days
If 4 ½ lives have left 8 g, how many g did we start with?
8g→16g →32g →64g →128g Answer: 128 g
13. A radioactive isotope with an original mass of 220g decayed until 13.75g remained. How many half-lives
were used during the decay process?
280g →110g →55g →27.5g →13.75g Answer: 4 half lives
14. A radioactive sample that decayed for 2.25 hours has an original mass of 150g. If the t 1/2 is 0.45 hours how
much of the sample remains after the decay period?
How many half lives are in 2.25 hours? 2.25 / 0.45 = 5
150g →75g →37.5 g→18.75g →9.375g →4.6875 g Answer: 4.7 g
15. What is the mass of the original nuclide that decayed for 4 half-lives if 10g remained after the decay
period?
10g →20g →40g →80g→160g answer: 160 g