Nuclear Chem Pset 4

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PA
Problem Set 4
Nuclear Chemistry
Chapters 4 and 25
Essay Due Oct 30th
th
Due Thursday Oct 24
Test Wednesday October 30th
 Your work is to be done on separate sheets of paper.
 All of the papers should be stapled together in the upper left hand corner with this
question sheet at the back of the packet.
 Each of your responses should be numbered the same way as it appears on this packet.
Conceptual Questions
1) State the law of conservation of mass.
2) Why are atoms unstable?
3) How do unstable atoms gain stability?
4) A radioactive element having atomic number 82 and atomic mass 214 loses a beta
0
particle, –1. What is the resulting particle?
5) What type of decay is the reaction below, and what isotope completes this nuclear
equation?
27
2
4
13Al + 1H  2He + ?
Practice Questions
6) Complete this chart on the three types of radioactive decay
Type
Symbol
Mass (amu)
Alpha
Beta
Gamma
Charge
238
7) If the radioactive atom 92U emits an alpha particle, the atom remaining is
represented by
(A)
238
92U
(B)
236
92Th
(C)
234
92U
(D)
32
30
234
234
90Th
(E) 91Pa
0
8) What term completes this equation? 14Si + ?  16S + –1e
4
(A)2He
2
1
(B)1H
0
(C)1H
(D) –1e
214
9) What particle is emitted when lead–214, 82Pb, undergoes natural radioactive
214
decay to bismuth–214, 83Bi?
4
(A)
an alpha particle, 2He
(B)
a beta particle, –1e
0
1
(C)
a proton, 1H
(D)
a neutron, 0n
1
Extension Question
10) Recently Alexander Valterovich Litvinenko was poisoned by radioactive
polonium-210.
a. Research who he was and why he was poisoned.
b. Find out what polonium-210 does to people.
c. Write the nuclear reaction of polonium-210 decaying into lead-206 via an
alpha decay.
Chapter 25 Nuclear Chemistry Read Chapter 25
After having read through chapter 25, respond to these conceptual questions.
11) Define the following terms:
a. critical mass
d.fusion
g.radioisotope
b.decay
e. half life
c. fission
f. transmutation
12) Make (or find) a graphical timeline of the development of modern atomic theory
with at least 10 important dates and/or discoveries.
After having read through chapter 25, respond to these practice questions.
13) Which type of radiation has a +2 charge?
a. Alpha
b. beta
c. gamma
d. neutron
14) Which type of radiation generates the highest energy – is the “hardest” to block?
a. Alpha
b. beta
c. gamma
d. neutron
15) Finish the following nuclear reactions. Tell if they are alpha or beta decays.
a.
b.
238
234
92
90
19
9
U
Th + ____
19
F  ___+ 10 Ne
c. 222
86
d.
4
Rn  ___ + 2He
210
85
0
At  ___ +-1
16) What element was the first man made (synthetic) by scientists?
17) How many grams of sample are left after 20 minutes if 100 grams start decaying
with a half life of 5 minutes?
18) How long will it take 100 grams of radioactive sample to decay so that only 6.25
grams remain and the samples half life is 3 days?
19) How long is the half life of an isotope if 2.0 grams of sample remain from a 64
gram sample after 30 years?
After having read through chapter 25, respond to these extension questions.
20) Element number 96 is named Curium. Do you think Marie and Pierre Curie did
enough in the advancement of science to have an element named after them?
Explain.
21) Thorium-231 is a radioactive isotope of thorium. It decays in ten steps to form
lead-207. The ten steps are:. Write this decay series.
Answers to Practice Problems
6) Complete this chart on the three types of radioactive decay
Type
Alpha
Beta
Gamma
Symbol



7) (D)
8) (B)
Mass (amu)
4 amu
0 amu
0 amu
9) (B)
13) a.
Charge
+2
-1
No charge
14) c
15)
a.
238
234
92
90
U
4
Th + 2He
c. 222
218
86
84
Rn 
alpha
b.
9 F  -1  + 10Ne
19
0
19
alpha
d.
85 At  86 Rn +- 1 
210
Beta
16) Oxygen-17
4
Po + 2 He
210
0
beta
17) 6.25 g
18) 12 days
19) 6 years
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