Atomic Structure and Radioactivity Study Guide
Know these terms:
9. Determine the mass number, the atomic number, the number of protons,
neutrons and electrons in each of the following:
A. Chromium-58
Mass #
Atomic #
58
24
Protons
24
Neutrons
34
Electrons
24
B. Selenium-60
Mass #
Atomic #
60
34
Protons
34
Neutrons
26
Electrons
34
D. U-238
Mass #
238
Atomic #
92
Protons
92
Neutrons
146
Electrons
92
E. Po-218
Mass #
218
Atomic #
84
Protons
84
Neutrons
134
Electrons
84
Atomic #
4
Protons
4
Neutrons
7
Electrons
4
Atomic #
99
Protons
99
Neutrons
155
Electrons
99
F.
11
4
Be
Mass #
11
G.
254
99
Es
Mass #
254
10.
Give the isotope symbol and number of neutrons in one atom of the
following elements. Show your calculations.
Barium – 138 82
Sulfur – 32 16
Carbon – 12 6
Hydrogen – 1 0
11. If you know ONLY the following information can you always
determine what the element is? (Yes/No).
number of protons yes
number of neutrons no
number of electrons in a neutral atom yes
number of electrons no
Atomic Structure and Radioactivity Study Guide
12. Write the nuclear equation for the following decay events:
A. Uranium-238 undergoes alpha decay
238
234
4
92𝑈 → 2𝐻𝑒 + 90𝑇ℎ
B. Hydrogen-3 undergoes beta decay
3
0
3
1𝐻 → −1𝑒 + 2𝐻𝑒
C. Polonium-218 undergoes alpha decay
218
4
84𝑃𝑜 → 2𝐻𝑒 +
D.
195
84
E.
18
7
Po →
N →
0
-1
4
2
He +
+
214
82𝑃𝑏
191
82𝑃𝑏
18
8𝑂
13. Write a series of nuclear decay equations as U-236 decays by the following
series: , β, β, , , . What will be the new isotope following the final decay?
220
86𝑅𝑛
14. If the half-life of a substance is 25 years, how much of a 64 gram substance
will remain after 125 years? 2 grams
15. How much time has passed if a sample of isotope X that was originally 40
grams has decayed down to 2.5 grams? The half-life of X is 24 hours. 96 hrs.
16. What are the benefits of nuclear fission and nuclear fusion? What are the
drawbacks of nuclear fission and nuclear fusion?
Type
Definition
Benefits
Drawbacks
*Large
amounts
of
Fission
Splitting a nucleus
Radioactive waste
energy from small
into 2 smaller
amount of fuel
nuclei
*No air pollution
Fusion
Combining 2 small
nuclei into a larger
nucleus
*Large amounts of
energy from small
amount of fuel
*No air pollution
*Only byproduct is
helium
*Abundant fuel source
(hydrogen)
Requires extreme
temperatures,
making it difficult
to contain