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Nuclear Radiation
Natural Radioactivity
Nuclear Equations
Producing Radioactive Isotopes
Half-Life
Nuclear Fission and Fusion
1
Subatomic Particles
• Protons- positive charge
In the nucleus
• Neutrons- neutral
• Electrons - negative charge
Outside the nucleus
2
Radiation
• Electro-magnetic radiation comes from
vibrating electrons, e.g., x-rays, light, uv
rays
• Nuclear Radiation comes from the nucleus
of an atom.
• Unstable nucleus emits a particle or energy
 alpha
 beta
 gamma
3
Alpha Particle
Same as a helium nucleus
(He)
4
2 He
or 
Two protons
Two neutrons
4
Beta Particle 
An electron emitted from the nucleus
0
e or

1
A neutron in the nucleus breaks down
1
1
0
n
H
+
e
0
1
-1
5
Gamma  Radiation
• Pure radiation
• Like an X-ray but comes from the nucleus
6
Radiation Protection
• Shielding
alpha – paper, clothing
beta – lab coat, gloves
gamma- lead, thick concrete
• Limit time exposed
• Keep distance from source
7
Radiation Protection
8
Nuclear Equations
Beta decay will cause an increase in the
atomic number since a Neutron has
changed into a proton. But the mass
remains the same.
Alpha decay will cause a decrease in
the atomic number and atomic mass
since 2 protons and 2 neutrons are
released as an alpha particle.
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Alpha decay
10
Beta decay
234Th
90

234Pa
91
+ 0e
1
beta particle
11
Gamma radiation
No change in atomic or mass number
11B
11B
5
5
+
0
0
boron atom in a
high-energy state
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Learning Check NR1
Write the nuclear equation for the beta
emitter Co-60.
13
Solution NR1
Write the nuclear equation for the
Beta emitter Co-60.
60Co
60Ni
27
28
+
0e
-1
14
Producing Radioactive
Isotopes
Bombardment of atoms produces
radioisotopes
59Co
27
cobalt
atom
+ 1n
0
neutron
56Mn
25
+
4H e
2
manganese alpha
radioisotope particle
15
Learning Check NR2
What radioactive isotope is produced in
the following bombardment of boron?
10B
5
+ 4He
? +
2
0
1n
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Solution NR2
What radioactive isotope is produced in
the following bombardment of boron?
10B
5
+ 4He
2
13N
7
+
1n
0
nitrogen
radioisotope
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Half-Life of a Radioisotope
The time for the radiation level to fall
(decay) to one-half its initial value
decay curve
initial
1
half-life
8 mg
4 mg
2
2 mg
3
1 mg
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Examples of Half-Life
Isotope
C-15
Ra-224
Ra-223
I-125
C-14
U-235
Half life
2.4 sec
3.6 days
12 days
60 days
5700 years
710 000 000 years
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Learning Check NR3
The half life of I-123 is 13 hr. How much
of a 64 mg sample of I-123 is left after
26 hours?
20
Solution NR3
Half-life time
=
13 hrs
26 hours
=
2 half-lives
Amount initial
=
64mg
Amount remaining = 64 mg x 1/2 x 1/2
= 16 mg
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Nuclear Fission
Fission
large nuclei break up
235U
92
+ 1n
0
139Ba
56
+
94Kr
36
+ 3 1n +
Energy
0
22
Fission
23
Nuclear Fusion
Fusion
small nuclei combine
2H
1
+
3H
4He
1
2
+ 1n +
Energy
0
Occurs in the sun and other stars
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Learning Check NR4
Indicate if each of the following are
(1) Fission
(2) fusion
A.
B.
C.
D.
Nucleus splits
Large amounts of energy released
Small nuclei form larger nuclei
Hydrogen nuclei react
Energy
25
Solution NR4
Indicate if each of the following are
(1) Fission
(2) fusion
A.
B.
C.
D.
1
1+2
2
2
Nucleus splits
Large amounts of energy released
Small nuclei form larger nuclei
Hydrogen nuclei react
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