Download Stable Vs Unstable Isotopes

Chapter 11
Stable Vs Unstable Isotopes
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For lighter atoms, a 1:1 ratio of neutrons to protons is stable
For larger atoms, it takes a greater number of neutrons to maintain stability
Beyond atomic number 83, all atoms are radioactive (unstable)
We call atoms that are radioactive radioisotopes.
Chapter 11
Nuclear Chemistry
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Nuclear chemistry involves a change to an atoms nucleus.
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Nuclear reactions are accompanied by tremendous energy changes as an unstable isotope
spontaneously undergoes changes.
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Some types of nuclear decay include:
1.  Alpha decay: An atom emits an alpha particle, thus the nucleus loses 2 protons and 2
neutrons. The atomic number decreases by 2, and the mass number decreases by 4.
2.  Beta decay: An atom emits a beta particle in the form of an electron when a neutron is
changed into a proton. The atomic number increases by 1 while the mass number remains
the same.
3.  Gamma decay: Usually accompanies alpha or beta emissions as an energy release.
Gamma rays cause no change in atomic or mass number since it is a form of energy only.
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Chapter 11
Nuclear Medicine
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Diagnostic Imaging: radioisotope is administered via ingestion or injection and allowed to
circulate to organ/area of interest in order to assess function.
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Radiation Therapy:
–  Internal RT: radioisotope is administered via injection, ingestion or surgical implantation with
the intent to release a dose of ionizing radiation high enough to kill malignant cells.
–  External RT: beam of radiation is aimed at the site of malignancy with the intent to cause
death to malignant cells.
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Chapter 11
Problems from Ch 11
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1. 
Co-60 is used in external beam radiation therapy. It undergoes beta decay which is
accompanied by the emission of gamma rays. Write an equation to show this decay:
2. 
Po-210 has been studied for use in heating spacecraft. It undergoes alpha decay. Write a
reaction to show this decay:
3. 
C-14 in the atmosphere undergoes beta decay. Write a reaction to show this decay:
Chapter 11
Write the identity of the missing nucleus for the following nuclear decay reaction:
Write the identity of the missing nucleus for the following nuclear decay reaction:
Write the identity of the missing nucleus for the following nuclear decay reaction:
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Chapter 11
The emission of a particle from an unstable nucleus is called
fission.
nuclear decay.
mutation.
translocation.
fusion.
Radioactivity is generally associated with which part of the atom?
the entire atom
electrons
protons
nucleus
neutrons
Which of the properties of radioisotopes make them useful as tracers in medical or agricultural applications?
I. Their chemical behavior is the same as nonradioactive isotopes.
II. They emit various types of radiation.
III. The nuclear reaction is unaffected by the chemical state of the isotope.
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Chapter 11
I and III
I and II
I only
none of these
all of these
When an atom loses an alpha particle:
its atomic number decreases by 2 units and its mass number decreases by 4 units
neither its atomic number nor its mass number changes
its mass number decreases by 1 unit but its atomic number remains unchanged
its atomic number increases by 1 unit but its mass number remains unchanged
Which product is formed by alpha emission from polonium-208? The atomic number of polonium is 84.
Which product is formed by beta emission from arsenic-75? The atomic number of arsenic is 33.
Which product is formed by gamma emission from technetium-99? The atomic number of technetium is 43.
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Chapter 11
Which nuclear reaction is an example of alpha emission?
Which product is formed by alpha emission from gold-185? The atomic number of gold is 79.
Which reaction is an example of a gamma emission?
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