Chapter 10
Nuclear Chemistry
Objectives:
 1. Describe the process of nuclear
decay
 2. Classify nuclear radiation as alpha
particles, beta particles or gamma
rays
 3. Balance nuclear equations
 4. Identify sources of nuclear
radiation and describe how nuclear
radiation affects matter
 5. Describe methods of detecting
nuclear radiation

 Definition:
radioactivity is the
process in which an unstable
atomic nucleus emits charged
particles and energy
 Definition: a radioisotope is any
atom containing un unstable
nucleus
 During nuclear decay, atoms of
one element can change into
atoms of a different element
altogether
Definition: an alpha particle is a
positively charged particle made up
of two protons and two neutrons (the
same as a helium nucleus)
 In alpha decay the product isotope
has two fewer protons & two fewer
neutrons than the reactant isotope
 Definition: a beta particle is an
electron emitted by an unstable
nucleus
 In beta decay the product isotope has
one proton more and one neutron
fewer than the reactant isotope

Definition: a gamma ray is a
penetrating ray of energy emitted by
an unstable nucleus
 Gamma radiation has no mass and
no charge
 During gamma decay the atomic
number & mass number remain the
same, but the energy of the nucleus
decreases
 Gamma radiation is very penetrating
compared to the alpha and beta

Definition: background radiation (also called
naturally occurring nuclear radiation) occurs
naturally in the environment
 When nuclear radiation exceeds background
levels, it can damage cells and tissues
 Nuclear radiation can ionize atoms including
alpha, beta and gamma
 Alpha can burn skin but is not serious
unless inhaled or eaten (ex: radon gas in
homes)
 Beta does more damage than alpha, but less
than gamma
 Gamma rays cause extensive damage

 Devices
that are used to detect
nuclear radiation include geiger
counters & film badges
 Film badges are worn by people
who work with radiation to detect
excessive levels
 Objectives:
 1.
Define half-life and relate halflife to the age of radioactive
isotope
 2. Compare and contrast nuclear
reaction rates with chemical
reaction rates
 3. Describe how radioisotopes are
used to estimate the age of
materials
Definition: half-life is the time required
for one half of a sample of a
radioisotope to decay
 Half life = total time of decay/half-life
 Q: If a radioactive sample has decayed
until one eighth of the original sample
remains, how many HL have elapsed?
 A: three HL ( ½ x ½ x ½ = 1/8 )
 Nuclear decay rates are constant
regardless of temperature, pressure or
surface area of the reactant (ex:
uranium-238)
 Chemical reactions are affected by local
conditions (temp, press, surface area,
etc.)

Carbon-14 has an unstable nucleus
and is radioactive
 It can be used to determine the age
of an object by comparing the
object’s carbon-14 levels with the
carbon-14 levels in the atmosphere
 146C --> 147N + 0-1e (half-life is 5720
years)
 Any object can be dated that is less
than 50,000 years old
 Older objects contain too little
carbon to be useful

 Objectives:
 1.
Explain what a particle
accelerator is
 2. Describe the process of nuclear
fission
 3. Explain how nuclear reactors
are used to produce energy
 4. Describe the process of nuclear
fusion
Definition: transmutation is
conversion of atoms of one element
into atoms of another element
 Scientists can bombard atomic nuclei
with high energy protons, neutrons
or alpha particles creating a new
element
 The equipment used to do this is
called a particle accelerator
 An important accelerator is located in
Illinois

Definition: fission is the splitting of an
atomic nucleus into two smaller parts
 Tremendous amounts of energy can
be produced from very small amounts
of mass by creating a chain reaction
 Definition: a chain reaction produces a
series of nuclear reactions by
releasing neutrons off an initial
nuclear trigger
 Speed of the reaction can vary
 Controlled reactions can be used to
produce electricity

Definition: critical mass is the smallest
possible mass of fissionable material
that can sustain a chain reaction
 The fissionable material in the United
States is radioactive uranium-235
 Electricity production with controlled
fission takes place at nuclear power
plants
 There are not many out West, although
some politicians are trying to change
that
 Currently, the majority of nuclear power
plants are located East of Nevada

Nuclear power plants do not emit air
pollutants unlike power plants that
burn fossil fuels
 Workers in nuclear plants must wear
protective clothing reducing
exposure to radiation
 The uranium-235 produces many
radioactive isotopes
 The waste must be stored for
hundreds of half-lives or thousands
of years

The waste must be isolated from
humans & the environment
 Operators have lost control of the
reactor from time to time
 During a nuclear core meltdown the
core melts and radioactive material
can be released
 A partial meltdown happened in
1986 in Chernobyl, Ukraine
 Chernobyl will be uninhabitable for
many generations to come
 It came to close to happening at
Three Mile Island, Pennsylvania

Definition: fusion is the process in
which the nuclei of two atoms combine
to form a larger nucleus
 A fraction of the reactant is converted
to energy during this process but we do
not yet have the technology to harness
the energy & convert it to electricity
 Fusion requires the temperature of the
sun in excess of 10 million degrees
 Definition: plasma is a state of matter
in which atoms have been stripped of
their electrons
 Fusion reactors do not yet exist due to
the temperatures required to start the
reaction & they must contain plasma
