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C.12ABC: Nuclear Chemistry
Atomic Structure and Nuclear Chemistry
RADIATION REFERENCE
Alpha Radiation
An alpha particle is a helium nucleus without any electrons. Since the helium atom has 2
protons and 2 neutrons in its nucleus, an alpha particle has a positive charge of +2.
4
2
Mass number
Atomic number
α
4
2 He
or
When alpha particles are emitted from a radioactive source and an electric field is applied, the
radiation beam is deflected towards the negative plate because of the attraction of the positive
alpha particles to the negative side of the electric field. Alpha particles are the largest type of
radiation particle and the most highly charged. They can be blocked by your hand, your
clothes, or a sheet of paper.
Electric field
+ + + + + + +
Paper
source
- - - - - - -
Below is an example of an alpha particle emission by radioactive Radium-224. Note that the
mass number and atomic number must be conserved in the nuclear equation.
224
88 Ra
à
4
2 He
+
220
86
Mass number 224 = 4 + 220
Atomic number 88 = 2 + 86
Rn
This is the balanced nuclear reaction of the radioactive decay of Radium-224 to Radon-220.
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C.12ABC: Nuclear Chemistry
Atomic Structure and Nuclear Chemistry
RADIATION REFERENCE
Beta Radiation
A beta particle is an electron that is emitted due to the radioactive decay of a nucleus. When
there is an uneven ratio of neutrons to protons in the nucleus, an excess neutron will split. This
results in a proton, which stays in the nucleus, and an electron, which is emitted as a beta
particle. Beta particles have a mass of zero and a charge of -1.
0
-1
Mass number
Atomic number
β
or
0
-1 e
When beta particles are emitted from a radioactive source and an electric field is applied, the
radiation beam is deflected towards the positive plate because of the attraction of the negative
beta particles to the positive side of the electric field. Beta particles are fast-moving and can
have high energy. They can be blocked by a piece of thin metal foil.
Electric field
+ + + + + + +
source
Paper
Metal
foil
- - - - - - -
Below is an example of a beta particle emission by radioactive Lead-210. Note that the mass
number and atomic number must be conserved in the nuclear equation.
210
82 Pb
à
0
-1 e
+
210
83
Mass number 210 = 0 + 210
Atomic number 82 = -1 + 83
Bi
This is the balanced nuclear reaction of the radioactive decay of Lead-210 to Bismuth-210.
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C.12ABC: Nuclear Chemistry
Atomic Structure and Nuclear Chemistry
RADIATION REFERENCE
Gamma Radiation
Gamma radiation is made up of high-energy photons or rays. Gamma rays have no mass and
no charge and are usually emitted along with alpha and beta decay as a way for the nucleus to
get rid of excess energy and achieve stability during a nuclear reaction.
Mass number
Atomic number
0
0
When gamma rays are emitted from a radioactive source and an electric field is applied, the
radiation beam is not deflected towards the positive or negative plate because gamma rays are
not charged.
γ
Electric field
source
+ + + + + + +
Paper
- - - - - - -
Foil
Concrete
Concret
e
High frequency gamma rays are the most penetrating type of radiation and the most harmful to
humans because they can cause tissue and cell damage. The high-energy photons can go
through paper and metal foil and can only be stopped by a thick lead shield or a concrete
block.
When a radioactive element undergoes radioactive decay and emits particle radiation, gamma
rays are frequently emitted as well. The nuclear reaction can be represented by a nuclear
equation in which only the nuclei of the elements are present. Gamma rays are not usually
included since they do not change the mass or charge of the products in the reaction, but can
be written to demonstrate the change from an excited state to a more stable, ground state.
60
27 Co
à
60
28
0
0
Ni + -1e + 2 0 γ
Cobalt-60 decays by beta emission to excited Nickel-60. Then the excited 60Ni falls to the
stable ground state of 60Ni by the emission of two gamma rays.
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C.12ABC: Nuclear Chemistry
Atomic Structure and Nuclear Chemistry
ISOTOPE REFERENCE
Isotope 1
The element phosphorus in found in many organic molecules. Adenosine triphosphate or ATP
is your body’s main form of energy. Phosphorus also helps maintain cell structure in the form
of phospholipids, keeping cells separate but permeable to compounds in your bloodstream.
Phosphorus-32 is a radioactive isotope of phosphorus that doctors use to examine and map
metabolic pathways in the human body. Cells that are multiplying abnormally accumulate
more phosphorus than normal cells. Injecting phosphorus-32 into the body allows doctors to
find cancerous tumors by using the radioactivity emitted from Phosphorus-32 as a tracer to
pinpoint the location of the tumors.
A common way to produce radioactive isotopes is to put a stable isotope in a nuclear reactor
and create a nuclear reaction that produces neutrons. The neutrons bombard everything in the
reactor, including the stable isotope, and it absorbs the neutrons into its nucleus. Radioactive
Phosphorus-32 is produced in a small-scale nuclear reactor by bombarding Sulfur-32 isotopes
with neutrons to make Sulfur-33. Unstable radioactive Sulfur-33 emits a proton to make
Phosphorus-32.
33
16 S
à
1
1H
+
32
15
P
Radioactive Phosphorus-32 is also unstable, and half of the amount that is produced is gone
after 14.5 days. Most radioactive isotopes that are used in nuclear medicine are selected
because they do not last very long. Their half-life, or the amount of time it takes for ½ of the
amount of the isotope to decay is short. The radioactive isotope soon forms a more stable
element that is not harmful to body tissues. Phosphorus-32 undergoes beta decay to form
Sulfur-32.
Phosphorus-32à beta decayà Sulfur-32
Some radioactive isotopes used in nuclear medicine are administered, and the radioactivity
emitted internally is monitored and used to construct an image of a specific area of the body’s
tissues. This is different from the way radioactivity is used in diagnostic x-rays, externally
passing the rays through the body to produce an image of the denser parts of the body.
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C.12ABC: Nuclear Chemistry
Atomic Structure and Nuclear Chemistry
ISOTOPE REFERENCE
Isotope 2
The element iodine is found in the human thyroid, an endocrine gland which controls the
body’s metabolism and regulates other systems in your body. When iodine is ingested, most of
it accumulates in the thyroid gland. Iodine-131 is a radioactive isotope of iodine that doctors
use to treat diseases associated with this gland. Grave’s disease, an illness caused by an
overactive thyroid, is easily treated by Iodine-131. The radioactive iodine is injected and over
time destroys the overactive thyroid gland, and the patient relies on synthetic hormones to
replace what the thyroid gland was producing.
A common way to produce radioactive isotopes is to put a stable isotope in a nuclear reactor
and create a nuclear reaction that produces neutrons. The neutrons bombard everything in the
reactor, including the stable isotope, and it absorbs the neutrons into its nucleus. Radioactive
Iodine-131 is produced in a small-scale nuclear reactor by bombarding Tellurium-130 with
neutrons to make Tellurium-131. Unstable radioactive Tellurium-131 undergoes beta decay to
make Iodine-131.
131
52 Te
à
0
-1
β
+
131
53
I
Radioactive Iodine-131 is also unstable, and half of the amount that is produced is gone after 8
days. Most radioactive isotopes that are used in nuclear medicine are selected because they
do not last very long. Their half-life, or the amount of time it takes for ½ of the amount of the
isotope to decay is short. The radioactive isotope soon forms a more stable element that is not
harmful to body tissues. Iodine-131 undergoes beta decay to form Xenon-131.
Iodine-131 à beta decay à Xenon-131
Some radioactive isotopes used in nuclear medicine are administered, and the radioactivity
emitted internally is monitored and used to destroy cells in a specific location in the body. This
is different from the way radioactivity is used in diagnostic x-rays, externally passing the rays
through the body to produce an image of the denser parts of the body. It is also safer because
smaller amounts of radiation are used, and the internal radioactive isotopes decay to a less
harmful form.
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C.12ABC: Nuclear Chemistry
Atomic Structure and Nuclear Chemistry
ISOTOPE REFERENCE
Isotope 3
Radioactive iridium is used to treat cancer of the head and breast by implanting small wires
made of Iridium-192 into the affected area. The radiation, in the form of gamma rays, emitted
over time from the radioactive source destroys the cancer cells surrounding it. This specialized
form of cancer treatment is called brachytherapy and is characterized by the use of implanted
sources of radiation designed to affect a small area of the body.
A common way to produce radioactive isotopes is to put a stable isotope in a nuclear reactor
and create a nuclear reaction that produces neutrons. The neutrons bombard everything in the
reactor, including the stable isotope, and the it absorbs the neutrons into its nucleus.
Radioactive Iridium-192 is produced in a small-scale nuclear reactor by bombarding naturally
occurring Iridium-191 with neutrons to make Iridium-192. Iridium-191 absorbs a neutron to
become radioactive Iridium-192.
191
77 Ir
+
1
0n
à
192
77
Ir
Radioactive Iridium-192 is unstable, and half of the amount that is produced is gone after 74
days. Most radioactive isotopes that are used in nuclear medicine are selected because they
do not last very long. Their half-life, or the amount of time it takes for ½ of the amount of the
isotope to decay is short. The radioactive isotope soon forms a more stable element that is not
harmful to body tissues. Iridium-192 undergoes beta decay to form Platinum-192.
Iridium-192 à beta decay à Platinum-192
Some radioactive isotopes used in nuclear medicine are administered, and the radioactivity
emitted internally is monitored and used to target and destroy cells in a specific area of the
body. This is different from the way radioactivity is used in diagnostic x-rays, externally
passing the rays through the body to produce an image of the denser parts of the body. It is
also safer because smaller amounts of radiation are used, and the internal radioactive isotopes
decay to a less harmful form.
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C.12ABC: Nuclear Chemistry
Atomic Structure and Nuclear Chemistry
ISOTOPE REFERENCE
Isotope 4
Gadolinium is an inner transition metal with slight magnetic properties. It is used in magnetic
resonance imaging (MRI) to enhance the contrast in medical images of the body and produce
a clearer picture. The gamma rays produced by radioactive gadolinium-153 are also used to
detect mineral density in the hip and back bones, making it useful in the diagnosis of
osteoporosis.
A common way to produce radioactive isotopes is to put a stable isotope in a nuclear reactor
and create a nuclear reaction that produces neutrons. The neutrons bombard everything in the
reactor, including the stable isotope, and it absorbs the neutrons into its nucleus. Radioactive
Gadolinium-153 is produced in a small-scale nuclear reactor when neutron enriched
Europium-153 undergoes beta decay.
153
63 Eu
à
0
-1
β
+
153
64
Gd
Radioactive Gadolinium-153 is unstable, and half of the amount that is produced is gone after
240 days. The half-life of a radioactive isotope is the amount of time it takes for ½ of the
amount of the isotope to decay. Gadolinium-153 undergoes beta decay to form Terbium-153, a
more stable element.
Gadolinium-153 à beta decay à Terbium-153
Some radioactive isotopes used in nuclear medicine are administered, and the radioactivity
emitted internally is monitored and used to construct an image of a specific area of the body’s
tissues. This is different from the way radioactivity is used in diagnostic x-rays, externally
passing the rays through the body to produce an image of the denser parts of the body. It is
also safer because smaller amounts of radiation are used, and the internal radioactive isotopes
decay to a less harmful form.
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