Nuclear Chemistry
CHEM 2124 – General Chemistry II
Alfred State College
Professor Bensley
Learning Objectives
 Learn the nuclear symbols for various
radioactive particles and forms of energy.
 Write a nuclear equation including deducing
the reactant or product of said reactions.
 List and predict the various types of
radioactive decay.
 Determine the product nucleus in
bombardment reactions.
 State the purposes of a Geiger counter.
Learning Objectives
 Define the radioactive decay constant.
 Define half-life and calculate half-life from
the decay constant.
 State the ways in which radioactive isotopes
are used for chemical analysis.
 Describe how isotopes are used for medical
therapy and diagnosis.
 Explain the difference between nuclear
fusion and nuclear fission reactions and
describe applications of each.
Nuclear Chemistry
I.
Introduction
A. Isotopes (Review)
B. Radioisotopes
C. Types of Radiation
1. Alpha Particle
2. Beta Particle
3. Gamma Rays
4. Positrons
Nuclear Chemistry
Nuclear Chemistry
II. Half Life (t1/2) - the time it takes for one-half of a
radioactive sample to decay
Table 10.2
Radioactive Decay of a 1.000-g
Sample of Iodine-131
Nuclear Chemistry
A. Decay Curves
– Mathematical relationship to use when calculating
half lives or amount of material left after x halflives have passed.
– Based on natural logarithms (ln)
– K = elimination rate constant = -0.693
M/M0 = e-KT/t1/2
ln(M/M0) = -KT/t1/2
Examples 1 and 2
A radioactive substance has a half-life of 7.5
minutes. If you initially have 100 grams of
this material, what mass would remain
after one hour?
You have a sample of radioactive material
that initially weighs 50 grams now weighs
only 12.75 grams after 24 hours. What is
the half-life of this substance?
Nuclear Chemistry
III. Health Effects of Radioactivity
A. Nuclear radiation will damage or kill rapidly
dividing cells such as bone marrow, skin,
and the reproductive and intestinal systems.
B. Food is irradiated, exposed to gamma
radiation, to kill any living organism in the
food.
Nuclear Chemistry
IV. Nuclear Reactions
A. Radioactive decay
B. Nuclear Equations
new
original
radiation
+
nucleus
nucleus
emitted
C. Alpha Emission (Decay) - decay of a nucleus by
emitting an a particle
Nuclear Chemistry
D. Beta Emission (Decay) - decay of a nucleus
by emitting a β particle; 1 neutron is lost and 1
proton is gained.
Nuclear Chemistry
E. Positron Emission (Decay) - decay of a nucleus
by emitting a positron, β+; 1 proton is lost and 1
neutron is gained.
Nuclear Chemistry
F. Gamma Emission (Decay) - decay of a nucleus
by emitting
99m
43 Tc
g radiation.
99
43 Tc
+
g
Commonly, g emission accompanies a or β emission.
Nuclear Chemistry
G. Nuclear fusion - the joining together of two light
nuclei to form a larger nucleus.
3
2
4
1
H
H +
He +
n
1
1
2
0
Nuclear Chemistry
H. Nuclear fission is the splitting apart of a heavy
nucleus into lighter nuclei and neutrons. It can
begin when a neutron bombards a uranium-235
nucleus:
91
142
235
1
1
+
+
+
n
n
3
Kr
Ba
U
36
56
92
0
0
Example 3
Complete the following nuclear reactions by filling in the
boxes with the appropriate numbers or symbols:
1.
238Pu
3.
238U
 234 U +

+ 0e
92
5.
85Kr
36
-1
 85Rb +
37
2.
14C
 14N +
4.
11B
 7Li
5
3
+
Examples 4 and 5
Write a balanced equation for the β-decay of
Phosphorus-32, a radioisotope used to treat
leukemia and other disorders.
Write a balanced equation for the positron
emission of fluorine-18, a radioisotope used for
imaging in PET scans.
Technetium-99m
Figure 10.5
Focus on Health and Medicine
Radioisotopes Used in Treatment
23
PET Scan showing Reduced Enzyme Levels in Various Body
Areas of a Smoker
Nuclear Chemistry
V. Modern Nuclear Reactors (Fission)
A. Chernobyl (1986)
Aerial Picture of Reactor
at Chernobyl Following
Nuclear Accident in
1986
Chernobyl - 2006
Interesting Facts
Nuclear Chemistry
B. Three Mile Island (3/28/1979)
Nuclear Chemistry
C. Fukushima Daiichi (2011)
D. Modern Nuclear Warheads
Top – Downtown
Nagasaki prior to
August, 1945
Bottom – Same
Area of Downtown
Nagasaki After
Atomic Bomb was
Dropped