Name: _____________________________
Pretest: _____/41
Posttest: _____/41
Ch 9 Pretest: Nuclear Energy
Match the vocabulary term on the left with the correct definition on the right.
F__ product of radioactive decay that is made
1. __
of a high-energy photon
C__ product of radioactive decay that is
2. __
made of a charged electron
A__ product of radioactive decay that is
3. __
made of two protons and two neutrons
D__ process by which a nucleus splits into
4. __
A. Alpha particle
B. Background Radiation
C. Beta particle
D. Fission
E. Fusion
F. Gamma Ray
two or more fragments and releases
neutrons and energy
G. Half-life
H. Nuclear Chain Reaction
I. Radioactivity
reactions
J. Radioactive tracer
K. Strong nuclear force
H__ a continuous series of nuclear fission
5. __
K__ counteracts repulsion between protons
6. __
and holds nucleus together
B__ found naturally in low levels from cosmic rays and from radioactive isotopes
7. __
in the soil and air
E__ process in which light nuclei combine at extremely high temperatures
8. __
I
forming heavier nuclei and releasing energy
9. __ __ matter and energy that is released from the nucleus during radioactive decay
J__ a radioactive material that is added to a substance so that its distribution
10. __
can be detected later.
G__ the time required for half of a sample of a radioactive substance to become
11. __
stable
Review stuff from ch 4 (4.2 specifically)
isotope_ An atom with a different number of neutrons is called a(n)…
12. _
mass number_ The number of protons and neutrons an atom has.
13. _
37
17
Cl
chlorine 37_ this is called….
14. _
17
20
15. – 16. It has _
_ protons and _
_ neutrons. (the bottom number is the
atomic number = # protons, the top number is the mass number = # protons + #
neutrons)
Half Life Graph and Calculations (Show work for full credit)
15 hrs._ A 208 g sample of sodium-24 decays to 13.0 g of
17. __
sodium-24 in 60.0 hours. What is the half-life of this
radioactive isotope?
208104522613 4 half lives
60 hrs. /4 half lives = 15 hrs
108 hrs.__ Chromium-48 has a short half-life of 21.6
18. _
hours. How long will it take 360.00 g of chromium-48
to decay to 11.25 grams?
360180904522.511.25
5 half lives
21.6(5) = 108
18 g____ Carbon-14 has a half-life of 5730 years.
19. ____
How much of a
144 gram sample of carbon-14 will remain after
17,190 years?
5730 + 5730 + 5730 = 17,190
3 half lives
144723618
To the right is a graph showing the radioactive
decay of a substance. Use it to answer the
following questions.
20. What is the half-life of this
substance?
kg
of
sub
stan
ce
2 days
21. How can you tell?
that’s how
long it takes to go
from 80 kg to 40 kg (1/2)
22. How many half-lives will it take for 5 kg of
the substance to remain?
8 days…just read off the graph
804020105
4 half-lives x 2 days each
23. After 6 days, how much of the substance will remain, if I started with 120 g?
15 g
Starting at 120, after 2 days 60 will remain,
after 2 more days (4 total) 30 will remain,
after 2 more days (6 total) 15 will remain
Types of Decay
Start with sulfur 35
35
16
S
24. – 25. What is the formula for an alpha () particle and what would be left if
sulfur 35 underwent alpha decay?
4
2
He
A helium nucleus, 2 protons and 2 neutrons
35
16
S
4
2
He
31
14
Si
26. – 27. What is the formula for a beta () particle and what would be left if
sulfur 35 underwent beta decay?
a neutron decays (-1) and forms a
proton (0) and an electron (e)
0
-1
e
35
16
S
0
-1
e
35
17
Cl
28. – 29. What is the formula for a gamma ray () and what would be left if sulfur 35
underwent gamma decay?

35
16
S*
Gamma rays are not matter; they are
just a photon of energy

35
16
S
Short Answer
30. – 33. Describe what happens during nuclear fission and nuclear fusion. How are
they similar and different?
Fission splits atoms, large nuclei become
small ones
Fusion puts them together, small nuclei
become large ones
Sim: both release energy,
small amount of mass converted into
large amount of energy (E= mc2)
Diff: split atoms vs. put together
Fusion makes heavier nuclei, fission
make lighter nuclei
34. What happens to the amounts of mass and energy in fission and fusion? (How
are they converted?)
In both, a small amount of mass converted into
large amount of energy
E= mc2 where E is the energy, m is the mass
and c is the speed of light
35. – 37. Different types of radiation can pass through different thickness and
densities of material. Label the three arrows below with the types of radiation
that they represent.
Beta particle 
Alpha particle 
Gamma ray 
38. – 39. List one advantage and one disadvantage of nuclear energy as a power
source.
+ lots of energy from little mass
+ reliable…energy is there
+ no air pollution (thermal pollution)
+ uses little fuel (Uranium or Hydrogen)
- radiation possibilities
- nuclear waste
- be careful controlling chain reaction
- expensive to set up/maintain
40. – 41. List two common, everyday activities that add to your amount of natural
nuclear radiation exposure.
Soil and rock…radon
Sun…gamma rays, esp. higher altitude
Xrays
smoking