Name:____________________________________ Period:________ Date:________________
Nuclear Decay Worksheet
Directions: Complete the following nuclear decay reactions (use a periodic table)
Fill in any blank spaces in the nuclear reactions.
Name the type of nuclear decay
(gamma, Alpha, or Beta)
K 
0
1
Pu 
4
2
1.
42
19
2.
239
94
3.
235
92
4.
60
27
5.
226
88
6.
37
19
7.
99
43
0
1
8.
________  24He 
208
81
9.
U
4
2
Co 
60
28
e
42
20
+
235
92
U
He +
He +
Ni +
Ca
231
90
T
0
1

Ra  24He  ________
K 
0
-1
e  ________
Tc  ________ 
9
4
0
0
e +
e
Tl
Be  11H  ________  24He
10. Write the nuclear equation for the release of a beta particle by uranium-237
11. Write the nuclear equation the alpha (α) decay of radon- 198
12. Write the nuclear equation for the decay of Po-210 if it undergoes 2 consecutive alpha decays
followed by a Beta decay followed by another alpha decay. What is the last element formed in this
chain of decay?
13.
a. Which subatomic particles are involved in nuclear reactions?
b. Which subatomic particles are involved in chemical reactions?
14. List the 3 types of radiation (α, β, γ) in order from least penetrating to most penetrating.
15. Fill blank boxes in the table below to summarize the three types of nuclear decay
Property
Composition
Alpha radiation
Beta radiation
Gamma radiation
Alpha particle
(He nucleus)
Symbol
,
0
1
e
Penetrating power
Very high
Effective Materials
to Shield/Protect
from radiation
16. Half-life Problems:
a) an isotope of cesium-137 has a half-life of 30 years. If 1 gram of cescium-137 disintegrates over a
period of 90 years, how many grams of cesium-137 would remain?
b) 384 grams of chromium-48 decays. After 6 half-lives, how many grams of the original nuclei would
remain?
c) If we start with 400 atoms of a radioactive substance, how many atoms would remain after one halflife? ________________ how many are left after two half-lives _______________? How many are left
after three half-lives? _________________________ how many left after four half-lives?____________
d) Based on the graph:
-How many years is one half-life for carbon-14?________________
-How many years will it be for carbon-14 to have three halflives?________________
-If only 25% of the original radioactive material is left, how many
years have passed? ___________________
16. Thorium-238 undergoes radioactive decay until a stable isotope is reached. Write the
reactions for the decay of Th-238. There are eleven steps beginning with Alpha decay with
each product becoming the reactant of the next decay. Circle the final Stable isotope.
• Alpha:
• Beta:
• Beta:
• Alpha:
• Alpha:
• Alpha:
• Alpha:
• Beta:
• Beta:
• Alpha:
• Beta:
Extra questions: DO NOT PRINT
Explain how energy loss and nuclear stability are related to radioactive decay.
What is the primary factor determining whether or not an atom is stable or unstable?
What is mass defect and why is it important?
What is the difference between nuclear fusion and nuclear fission?