Download II. Radioactive Decay

CHAPTER 24
Nuclear
Chemistry
I
II
III
IV
(p. 858-899)
2
Table Of Contents
CHAPTER
4
Section 24.1
Nuclear Radiation
Section 24.2
Radioactive Decay
Section 24.3
Nuclear Reactions
Section 24.4
Applications and Effects of Nuclear Reactions
CHAPTER 24
Nuclear
Chemistry
I
II
III
IV
I. Nuclear Radiation
SECTION
2
Nuclear Radiation
4.1
• Summarize the events that led nucleus: the extremely small,
to understanding radiation.
positively charged, dense center
of an atom that contains
positively charged protons,
• Identify alpha, beta, and
neutral neutrons, and is
gamma radiations in terms of surrounded by empty space
composition and key
through which one or more
properties.
negatively charged electrons
move
Student Learning essential questionsSection 1
• How was radioactivity discovered and studied?
• What are the key properties of alpha, beta, and
gamma radiation?
SECTION
Nuclear Radiation
2
4.1
Isotope
Radioisotope
X-ray
penetrating power
Under certain conditions, some nuclei can emit
alpha, beta, or gamma radiation.
Warm -up
• List the three different types of radiation and
their charges.
• Tell me the composition of the radiation type
that can not penetrate paper because it is too
large.
1. Alpha, +2; Beta, _1; Gamma, 0
2. Alpha, 2 protons and 2 neutrons
SECTION
2
Nuclear Radiation
4.1
The Discovery of Radiation
• Nuclear reactions are different from other types of
reactions.
• Nuclear chemistry is concerned with the structure of
atomic nuclei and the changes they undergo.
• Marie Curie and her husband Pierre isolated the first
radioactive materials.
SECTION
2
Nuclear Radiation
4.1
The Discovery of Radiation (cont.)
Warm-Up
C. Johannesson
Isotopes
Isotopes …
…of the same element have the
same number of protons and
electrons but different numbers of
neutrons.
Therefore, isotopes of the same
element have different masses.
Isotopes …
…don’t have to be radioactive.
Some isotopes are unstable and decay, releasing alpha or beta
particles, or gamma rays.
But, there are many stable isotopes that don’t decay.
Isotopes …
…have different mass numbers but the same atomic number.
Atomic number - the number of protons in the nucleus of an atom.
Mass number - the sum of the protons and neutrons in the nucleus.
Symbols for Isotopes
Mass number
A is the
symbol A
for mass Z
number
Atomic
number
E
Symbol of
element
Z is the symbol for
atomic number
Symbols for Isotopes
Mass number
235
92
Atomic
number
U
Symbol of
Element
An isotope of uranium
Symbols for Isotopes
Mass number
This form solves the
word processor
235
dilemma.
92
U
Symbol of
Element
Atomic number
An isotope of uranium
Symbols for Isotopes
Symbol of
Find U in the periodic
Element
table.
U-235
Z = 92
How do you know the
Mass numbe
atomic number?
Some elements have several Isotopes
Lead has four naturally occurring isotopes, Pb-204, Pb-206, Pb-207,
and Pb-208; but there are 23 man-made isotopes of lead.
Some elements have several Isotopes
Bismuth has only one naturally occurring isotope, Bi-209, but
there are 22 man-made isotopes of bismuth.
How are isotopes of the same element alike
and different?
Different:
Alike:
1. Number of
1. Number of
neutrons
protons and
electrons
2. Atomic number 2. Mass Number
3. Atomic mass of
3. Chemical
the isotopes
properties
SECTION
2
Nuclear Radiation
4.1
Types of Radiation
Isotope- Atoms of the same element with different
number of neutrons.
• Isotopes of atoms with unstable nuclei are called
radioisotopes.
• Unstable nuclei emit radiation (release energy) to attain
more stable atomic configurations in a process called
radioactive decay.
• The three most common types of radiation are alpha,
beta, and gamma.
SECTION
2
Nuclear Radiation
4.1
Types of Radiation (cont.)
A. Types of Radiation
• Alpha particle ()
– helium nucleus
 Beta particle (-)
 electron
4
2
0
-1
He
e
2+
1-
 Positron (+)
0
1 e
 positron
 Gamma ()
 high-energy photon
paper
lead
1+
concrete
0
SECTION
2
Nuclear Radiation
4.1
Types of Radiation (cont.)
• Alpha particles have the same composition as a
helium nucleus—two protons and two neutrons.
• Because of the protons, alpha particles have a 2+ charge.
• Alpha radiation consists of a stream of particles.
SECTION
2
Nuclear Radiation
4.1
Types of Radiation (cont.)
• Alpha radiation is not very penetrating—a single sheet
of paper will stop an alpha particle.
SECTION
2
Nuclear Radiation
4.1
Types of Radiation (cont.)
• Beta particles are very fast-moving electrons emitted
when a neutron is converted to a proton.
• Beta particles have insignificant mass and a 1– charge.
SECTION
2
Nuclear Radiation
4.1
Types of Radiation (cont.)
• Beta radiation is a stream of fast moving particles with
greater penetrating power—a thin sheet of foil will stop
them.
SECTION
2
Nuclear Radiation
4.1
Types of Radiation (cont.)
• Gamma rays are high-energy electromagnetic radiation.
• Gamma rays have no mass or charge.
• Gamma rays almost always accompany alpha and beta
radiation.
• X rays are a form of high-energy electromagnetic
radiation emitted from certain materials in an excited
state. (gamma rays)
SECTION
2
Nuclear Radiation
4.1
Types of Radiation (cont.)
• The ability of radiation to pass through matter is
called its penetrating power.
• Gamma rays are highly penetrating because they have no
charge and no mass.
SECTION
Section Check
2
4.1
Why do radioisotopes emit radiation?
A.
to balance charges in the nucleus
B.
to release energy
C.
to attain more stable atomic configurations
D.
to gain energy
SECTION
Section Check
2
4.1
X rays are most similar to what type of nuclear
emissions?
A.
gamma rays
B.
alpha particles
C.
beta particles
D.
delta waves
CHAPTER 24
Nuclear
Chemistry
I
II
III
IV
II. Radio Active
Decay
SECTION
2
Radioactive Decay
4.2
• Explain why certain nuclei are
radioactive.
• Apply your knowledge of
radioactive decay to write
balanced nuclear equations.
• Solve problems involving
radioactive decay rates.
radioactivity: the process by
which some substances
spontaneously emit radiation
Student Learning essential questionsSection 2
• Why are certain nuclei radioactive?
• How can you use radioactive decay rates to analyze
samples of radioisotopes?
SECTION
Radioactive Decay
2
4.2
Transmutation
half-life
Unstable nuclei can break apart spontaneously,
changing the identity of atoms.
SECTION
2
Radioactive Decay
4.2
Nuclear Stability
• Except for gamma radiation, radioactive decay
involves transmutation, or the conversion of an
element into another element.
• Protons and neutrons are referred to as nucleons.
• All nucleons remain in the dense nucleus because of the
strong nuclear force.
B. Nuclear Decay
• Alpha Emission
238
92
parent
nuclide
U
Th  He
234
90
daughter
nuclide
4
2
alpha
particle
Numbers must balance!!
B. Nuclear Decay
• Beta Emission
131
53
I
131
54
Xe  e
0
-1
electron
 Positron Emission
38
19
K
38
18
Ar 
0
1
e
positron
B. Nuclear Decay
• Electron Capture
106
47
Ag  e 
0
-1
106
46
Pd
electron
 Gamma Emission
 Usually follows other types of decay.
 Transmutation
 One element becomes another.
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay
• Atoms can undergo different types of decay—beta
decay, alpha decay, positron emission, or electron
captures—to gain stability.
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay (cont.)
• In beta decay, radioisotopes above the band of
stability have too many neutrons to be stable.
• Beta decay decreases the number of neutrons in the
nucleus by converting one to a proton and emitting a beta
particle.
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay (cont.)
• In alpha decay, nuclei with more than 82 protons are
radioactive and decay spontaneously.
• Both neutrons and protons must be reduced.
• Emitting alpha particles reduces both neutrons and
protons.
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay (cont.)
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay (cont.)
• Nuclei with low neutron to proton ratios have two
common decay processes.
• A positron is a particle with the same mass as an electron
but opposite charge.
• Positron emission is a radioactive decay process that
involves the emission of a positron from the nucleus.
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay (cont.)
• During positron emission, a proton in the nucleus is
converted to a neutron and a positron, and the positron
is then emitted.
• Electron capture occurs when the nucleus of an atom
draws in a surrounding electron and combines with a
proton to form a neutron.
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay (cont.)
SECTION
2
Radioactive Decay
4.2
Types of Radioactive Decay (cont.)
B. Nuclear Decay
• Why nuclides decay…
– need stable ratio of neutrons to protons
238
92
U
I
131
54
K
38
18
131
53
38
19
106
47
Th  He
234
90
4
2
Xe  e
Ar 
Ag  e 
0
-1
0
-1
0
1
106
46
e
Pd
DECAY SERIES TRANSPARENCY
C. Half-life
• Half-life (t½)
– Time required for half the atoms of a radioactive
nuclide to decay.
– Shorter half-life = less stable.
C. Half-life
mf  m ( )
1 n
i 2
mf: final mass
mi: initial mass
n: # of half-lives
C. Half-life/Warm-Up
 Fluorine-21 has a half-life of 5.0 seconds. If you start with 25 g of
fluorine-21, how many grams would remain after 60.0 s?
 n = (t) ÷ (T); t = total elapsed time, T = length of half life.
GIVEN:
WORK:
T½ = 5.0 s
mf = mi (½)n
mi = 25 g
mf = (25 g)(0.5)12
mf = ?
mf = 0.0061 g
t = 60.0 s
n = 60.0s ÷ 5.0s =12
C. Johannesson
C. Half-life
The half-life of radium-224 is 3.66 days. What was the
original mass of radium-224 if 0.0500 grams remains after
7.32 days? Show all work!
GIVEN:
WORK:
T½ = 3.66 days
mi = ?
mf = 0.0500
mf = mi (½)n
mf = (mi)(0.5)2
mf = 0.0500 g
.0500 g = (mi)(0.5)2
mi = 0.0500 g ÷ 0.25 = 0.2 g
Elapsed time (t) = 7.32 days
n = 7.32 days ÷ 3.66 days
= 2.00
C. Johannesson
C. Half-life
Exactly 1/16th of a given amount of protactinum-234
remains after 26.75 hours. What is the half-life of
protactinum-234? Show all work!
GIVEN:
WORK:
Lets say original amount
(mi) = 100g proctactinum234.
mf = mi (½)n
n = 4- half lives
T = 26.75 ÷ 4 = 6.69 hours
100 g X (1/16) -= 6.25 g
50 g = 1st half-life
25 g = 2nd half-life
12.5 g = 3rd half-life
6.25 g = 4th half-life
C. Johannesson
SECTION
2
Radioactive Decay
4.2
Radioactive Decay Rates (cont.)
SECTION
2
Radioactive Decay
4.2
Radioactive Decay Rates (cont.)
SECTION
2
Radioactive Decay
4.2
Radioactive Decay Rates (cont.)
• The process of determining the age of an object by
measuring the amount of certain isotopes is called
radiochemical dating.
• Carbon-dating is used to measure the age of artifacts that
were once part of a living organism.
SECTION
Section Check
2
4.2
The process of converting one element into
another by radioactive decay is called ____.
A.
half-life
B.
nuclear conversion
C.
transmutation
D.
trans-decay
SECTION
Section Check
2
4.2
An unknown element has a half-life of 40
years. How much of a 20.0g sample will be left
after 120 years?
A.
0.00g
B.
2.50g
C.
5.00g
D.
7.50g
CHAPTER 24
Nuclear
Chemistry
I
II
III
IV
III. Nuclear
Reactions
SECTION
2
Nuclear Reactions
4.3
• Understand that mass and
energy are related.
• Compare and contrast
nuclear fission and nuclear
fusion.
• Explain the process by which
nuclear reactors generate
electricity.
mass number: the number
after an element’s name,
representing the sum of its
protons and neutrons
Student Learning essential questionsSection 3
• How are nuclear equations balanced?
• How are mass and energy related?
• How do nuclear fission and nuclear fusion compare
and contrast?
• What is the process by which nuclear reactors
generate electricity?
SECTION
Nuclear Reactions
2
4.3
nuclear fission
nuclear fusion
Fission, the splitting of nuclei, and fusion, the
combining of nuclei, release tremendous amounts
of energy.
SECTION
2
Nuclear Reactions
4.3
Induced Transmutation
• One element can be converted into another by
spontaneous emission of radiation.
• Elements can also be forced to transmutate by
bombarding them with high-energy alpha, beta, or
gamma radiation.
Warm-Up: Writing Nuclear Equations
• Write a balanced equation for the alpha decay of
thorium-232. Turn to Pg. 868, Table 3, and page 869
in Text book, to help getting started.
Answer:
Warm-Up:Balancing a Nuclear reaction
• NASA uses the alpha decay of plutonium-238,
as a heat source on spacecraft. Write a balanced equation for
this decay.
Analyze this problem- You are given that a plutonium atom undergoes alpha decay and
forms an unknown product. Plutonium-238 is the initial reactant, while the alpha
particle is one of the products of the reaction. The reaction is summarized in the
equation below.
Determine the unknown product of the reaction, X
SECTION
2
Radioactive Decay
4.2
Writing and Balancing Nuclear Equations
• Nuclear reactions are expressed by balanced nuclear
equations.
• In balanced nuclear equations, mass numbers and charges
are conserved.
–Ex. A plutonium-238 atom undergoes alpha decay, write a
balanced equation for this decay.
SECTION
2
Radioactive Decay
4.2
Writing and Balancing Nuclear Equations
SECTION
2
Nuclear Reactions
4.3
Induced Transmutation (cont.)
• The process of striking nuclei with high-velocity
charged particles is called induced transmutation.
SECTION
2
Nuclear Reactions
4.3
Induced Transmutation (cont.)
• Particle accelerators use electrostatic and magnetic
fields to accelerate charged particles to very high
speed.
• Transuranium elements are the elements with atomic
numbers 93 and higher, immediately following uranium.
SECTION
2
Nuclear Reactions
4.3
Nuclear Reactions and Energy
• Mass and energy are related.
• Loss or gain in mass accompanies any reaction that
produces or consumes energy.
SECTION
2
Nuclear Reactions
4.3
Nuclear Reactions and Energy (cont.)
• Most chemical reactions produce or consume so little
energy that the accompanying changes in mass are
negligible.
• Energy released from nuclear reactions have significant
mass changes.
SECTION
2
Nuclear Reactions
4.3
Nuclear Reactions and Energy (cont.)
• The mass of a nucleus is always less than the sum of
the masses of the individual protons and neutrons that
comprise it.
• The difference between a nucleus and its component
nucleons is called the mass defect.
• Binding together or breaking an atom’s nucleons involves
energy changes.
SECTION
2
Nuclear Reactions
4.3
Nuclear Reactions and Energy (cont.)
• Nuclear binding
energy is the amount
of energy needed to
break 1 mol of nuclei
into individual
nucleons.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fission
• The splitting of nuclei into fragments is known as
nuclear fission.
• Fission is accompanied with a very large release of
energy.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fission (cont.)
• Nuclear power plants use fission to produce electricity
by striking uranium-235 with neutrons.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fission (cont.)
• Each fission of U-235 releases two additional neutrons.
• Each of those neutrons can release two more neutrons.
• The self-sustaining process is called a chain reaction.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fission (cont.)
SECTION
2
Nuclear Reactions
4.3
Nuclear Fission (cont.)
• Without sufficient mass, neutrons escape from the
sample before starting a chain reaction.
• Samples with enough mass to sustain a chain reaction are
said to have critical mass.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fission (cont.)
Nuclear fission
Fission fragment
U-235
U-235
Neutrons
Neutron
Fission fragment
U-235
Nuclear fission
Neutrons
U-235
U-235
Fission fragment
These U-235 atoms
can split when hit by
neutrons, and release
more neutrons,
starting a chain
reaction.
Nuclear fission
To picture a chain reaction, imagine 50 mousetraps in a wire cage.
And on each mousetrap are two ping-pong balls.
Now imagine dropping one more ping-pong ball into the cage …
Detail of ping-pong balls
on mousetraps.
http://www.physics.montana.edu/demonstrations/video/modern/demos/mousetrapchainreaction.html
http://www.physics.montana.edu/demonstrations/video/modern/demos/mousetrapchainreaction.html
Nuclear fission
As the chain reaction proceeds, energy
is released as heat energy.
This energy originally held the
nucleus together.
Billions of splitting atoms releases a
huge amount of heat energy.
Nuclear fission
This heat energy can be harnessed to boil water,
creating steam,
that can spin a turbine,
that can turn a generator,
creating electricity.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fusion
• It is possible to bind together two or more lighter
elements (mass number less
than 60).
• The combining of atomic nuclei is called nuclear fusion.
• Nuclear fusion is capable of releasing very large amounts
of energy.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fusion (cont.)
• Fusion has several advantages over fission.
− Lightweight isotopes are abundant.
− Fusion products are not radioactive.
− However, fusion requires extremely high energies to initiate and
sustain a reaction.
SECTION
2
Nuclear Reactions
4.3
Nuclear Fusion (cont.)
• Fusion reactions are also known as thermonuclear
reactions.
• Many problems must be solved before nuclear fusion is a
practical energy source.
SECTION
2
Nuclear Reactions
4.3
Nuclear Reactors
• Nuclear fission produces the energy generated by
nuclear reactors.
• The fission within a reactor is started by a neutronemitting source and is stopped by positioning the control
rods to absorb virtually all of the neutrons produced in
the reaction.
SECTION
2
Nuclear Reactions
4.3
Nuclear Reactors (cont.)
• The reactor core contains a reflector that reflects
neutrons back into the core, where they react with fuel
rods.
• Nuclear reactors produce highly radioactive nuclear
waste.
• Breeder reactors produce more fuel than they consume.
SECTION
2
Nuclear Reactions
4.3
Nuclear Reactors (cont.)
SECTION
Section Check
2
4.3
Bombarding a nuclei with charged particle in
order to create new elements is called ____.
A.
nuclear conversion
B.
nuclear decay
C.
induced decay
D.
induced transmutation
SECTION
2
Section Check
4.3
Thermonuclear reactions involve:
A.
splitting nuclei into smaller fragments
B.
fusing nuclei together to form larger particles
C.
bombarding nuclei with charged particles
D.
generating electricity in a nuclear reactor
CHAPTER 24
Nuclear
Chemistry
I
II
III
IV
IV- Applications and Effects of
Nuclear Reactions
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
• Describe several methods used to detect and measure radiation.
• Explain an application of radiation used in the treatment of
disease.
• Describe some of the damaging effects of radiation on biological
systems.
isotope: an atom of the same element with the same number of
protons but different number of neutrons
Student Learning essential questionsSection 4
• What are several methods used to detect and
measure radiation?
• How is radiation used in the treatment of disease?
• What are some of the damaging affects of radiation
on biological systems?
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
ionizing radiation
radiotracer
Nuclear reactions have many useful applications,
but they also have harmful biological effects.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Detecting Radioactivity
• Radiation with enough energy to ionize matter it
collides with is called ionizing radiation.
• The Geiger counter uses ionizing radiation to detect
radiation.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Detecting Radioactivity (cont.)
• A scintillation counter detects bright flashes when
ionizing radiation excites electrons of certain types of
atoms.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Uses of Radiation
• When used safely, radiation can be very useful.
• A radiotracer is a radioactive isotope that emits nonionizing radiation and is used to signal the presence of an
element or specific substrate.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Uses of Radiation (cont.)
• Radiation can damage or destroy healthy cells.
• Radiation can also destroy unhealthy cells, such as cancer
cells.
• Unfortunately, radiation therapy also destroys healthy
cells in the process of destroying cancerous cells.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Biological Effects of Radiation
• Radiation can be very harmful.
• The damage depends on type of radiation, type of tissue,
penetrating power, and distance from the source.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Biological Effects of Radiation (cont.)
• High energy radiation is dangerous because it
produces free radicals.
• Free radicals are atoms or molecules that contain one or
more unpaired electrons.
• Free radicals are highly reactive.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Biological Effects of Radiation (cont.)
• Two units measure doses of radiation.
• The rad stands for Radiation-Absorbed Dose, which is
the amount of radiation that results in 0.01 J of energy
per kilogram of tissue.
• The rad does not account for the type of tissue that is
absorbing the radiation.
• The rad is multiplied by a factor related to its effect on
the tissue involved and is called the rem, Roentgen
Equivalent for Man.
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Biological Effects of Radiation (cont.)
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Biological Effects of Radiation (cont.)
• I1d12 = I2d22 where I = intensity and
d = distance.
Nuclear reactor
Nuclear reactor
Containment building
Nuclear reactor
Reactor core
Heat exchanger
Steam generator
Steam to
turbine
Water from
cooling lake
Water circulates in the core
Containment building
Nuclear reactor
Reactor core
Cadmium control rods – absorb neutrons
Steam to
turbine
Water from
cooling lake
Water circulates in the core
Containment building
The water in the core
serves two functions.
(1) The water cools the core and carries away heat.
(2) Water is a moderator. The water slows the neutrons so
that they can cause fission. Fast neutrons do not cause
Reactor core
fission.
Nuclear reactor
Steam to
turbine
Water from
cooling lake
Water circulates in the core
Containment building
Nuclear reactor
Reactor core
Water from
cooling lake
Water circulates in the core
Containment building
Nuclear reactor
Reactor core
Heat exchanger
Steam generator
Water from
cooling lake
Water circulates in the core
Containment building
Nuclear reactor
Reactor core
Heat exchanger
Steam generator
Water from
cooling lake
Water circulates in the core
Containment building
Nuclear reactor
Reactor core
Heat exchanger
Steam generator
Steam to
turbine
Water from
cooling lake
Water circulates in the core
From nuclear energy to…
Heat exchanger
Steam generator
Steam to
turbine
Water from
cooling lake
Transmission wires
turbine
generator
Condensed steam
Cooling towers or
lake
Electrical energy
Heat exchanger
Steam generator
Steam to
turbine
Water from
cooling lake
Transmission wires
turbine
generator
Condensed steam
Cooling towers or
lake
Electrical energy
Heat exchanger
Transmission
wires
This
part of the system
is the same
Steam generator
regardless of how the steam is
generator
produced.
Theturbine
heat can come
from
Steam to
turbine
nuclear energy or byCondensed
burningsteam
coal,
natural
gasfrom
or fuel oil.
Water
cooling lake
Cooling towers or
lake
Electrical energy
In fact, the only purpose of a
nuclear reactor
is to boil water.
Pros and cons
Cheap, plentiful power, no CO2,
nuclear waste, terrorist attack,
running out of oil and coal, on-site
storage, breeder reactors,
transportation of spent fuel, “not in
my backyard”, …
SECTION
Section Check
2
4.4
What is a radioisotope that emits non-ionizing
radiation and is used to signal the presence of
certain elements called?
A.
rad
B.
rem
C.
radiotracer
D.
free radical
SECTION
Section Check
2
4.4
Radiation with enough energy to cause tissue
damage by ionizing the particles it collides
with is called ____.
A.
alpha decay
B.
beta decay
C.
gamma radiation
D.
ionizing radiation
SECTION
2
Nuclear Radiation
4.1
Study Guide
Key Concepts
• Wilhelm Roentgen discovered X rays in 1895.
• Henri Becquerel, Marie Curie, and Pierre Curie pioneered the fields
of radioactivity and nuclear chemistry.
• Radioisotopes emit radiation to attain more-stable atomic
configurations.
SECTION
2
Radioactive Decay
4.2
Study Guide
Key Concepts
• The conversion of an atom of one element to an atom of another by
radioactive decay processes is called transmutation.
• Atomic number and mass number are conserved in nuclear reactions.
• A half-life is the time required for half of the atoms in a radioactive
sample to decay.
• Radiochemical dating is a technique for determining the age of an
object by measuring the amount of certain radioisotopes remaining in
the object.
SECTION
2
Nuclear Reactions
4.3
Study Guide
Key Concepts
• Induced transmutation is the bombardment of nuclei with particles
in order to create new elements.
• In a chain reaction, one reaction induces others to occur. A
sufficient mass of fissionable material is necessary to initiate
the chain reaction.
• Fission and fusion reactions release large amounts of energy.
E = mc2
SECTION
2
Applications and Effects of Nuclear Reactions
4.4
Study Guide
Key Concepts
• Different types of counters are used to detect and measure
radiation.
• Radiotracers are used to diagnose disease and to analyze chemical
reactions.
• Short-term and long-term radiation exposure can cause damage to
living cells.
Nuclear Chemistry
2
CHAPTER
4
Chapter Assessment
The half-life of a radioisotope is:
A.
one-half its total life
B.
2500 years
C.
the amount of time it takes to completely decay
D.
the amount of time it takes for one-half to decay
2
CHAPTER
Nuclear Chemistry
4
Chapter Assessment
What is a positron?
A.
a nucleon with the same mass as a neutron
positive charge
and a
B.
a nucleon with the same mass as a proton and
negative charge
C.
a nucleon with the same mass as an electron and a
positive charge
D.
a type of radioactive emission with a negative
charge
a
Nuclear Chemistry
2
CHAPTER
4
Chapter Assessment
What is the force that holds the protons and neutrons
together in the nucleus of an atom?
A.
nuclear magnetic force
B.
strong nuclear force
C.
ionic bonding
D.
nuclear bond
Nuclear Chemistry
2
CHAPTER
4
Chapter Assessment
During positron emission, a proton is converted to:
A.
a neutron and electron
B.
an electron and positron
C.
a proton and neutron
D.
a neutron and positron
Nuclear Chemistry
2
CHAPTER
4
Chapter Assessment
A thermonuclear reaction is also called ____.
A.
nuclear fission
B.
nuclear fusion
C.
mass defect
D.
critical mass
Nuclear Chemistry
2
CHAPTER
4
Standardized Test
Practice
Which statement is NOT true of beta particles?
A.
They have the same mass as an electron.
B.
They have a charge of 1+.
C.
They are less penetrating than alpha particles.
D.
They are represented by 0-1β.
Nuclear Chemistry
2
CHAPTER
4
Standardized Test
Practice
The site that oxidation occurs at in a battery is called ____.
A.
anode
B.
cathode
C.
nothode
D.
salt bridge
Nuclear Chemistry
2
CHAPTER
4
Standardized Test
Practice
A solution of 0.500M HCl is used to titrate 15.00mL if KOH
solution. The end point of the titration is reached after
25.00 mL of HCl is added. What is the concentration of
KOH?
A.
9.00M
B.
1.09M
C.
0.833M
D.
0.015M
Nuclear Chemistry
2
CHAPTER
4
Standardized Test
Practice
The half-life of K-40 is 1.26 × 109 years. How much of a
10.0g sample will be left after 200 million years?
A.
8.96g
B.
8.03g
C.
7.75g
D.
4.99g
Nuclear Chemistry
2
CHAPTER
4
Standardized Test
Practice
Elements above the band of stability are radioactive
and decay by ____.
A.
alpha decay
B.
beta decay
C.
positron emission
D.
electron capture
Nuclear Properties Table
Property
Alpha
Beta
Gamma
Greek Letter
Symbol
Actually is…
Stop!
Atomic number
Mass number
Relative mass
Relative charge
Penetrating
Shielding
Complete the chart on
notebook paper, then
continue.
Nuclear Properties Table
Property
Greek Letter
Symbol
Actually is…
Atomic number
Mass number
Relative mass
Relative charge
Penetrating
Shielding
Alpha
Beta
Gamma
Nuclear Properties Table
Property
Greek Letter
Symbol
Actually is…
Atomic number
Mass number
Relative mass
Relative charge
Penetrating
Shielding
Alpha
Beta
Gamma



Nuclear Properties Table
Property
Greek Letter
Symbol
Actually is…
Atomic number
Mass number
Relative mass
Relative charge
Penetrating
Shielding
Alpha
Beta
Gamma



4
2He
0
-1e
NA
Nuclear Properties Table
Property
Greek Letter
Symbol
Actually is…
Atomic number
Mass number
Relative mass
Relative charge
Penetrating
Shielding
Alpha
Beta
Gamma



4
2He
0
-1e
NA
He nucleus
electron
EM energy
Nuclear Properties Table
Property
Greek Letter
Symbol
Actually is…
Atomic number
Mass number
Relative mass
Relative charge
Penetrating
Shielding
Alpha
Beta
Gamma



4
2He
0
-1e
NA
He nucleus
electron
EM energy
2
-1
NA
Nuclear Properties Table
Property
Alpha
Beta
Gamma



4
2He
0
-1e
NA
He nucleus
electron
EM energy
Atomic number
2
-1
NA
Mass number
4
0
NA
Greek Letter
Symbol
Actually is…
Relative mass
Relative charge
Penetrating
Shielding
Nuclear Properties Table
Property
Alpha
Beta
Gamma



4
2He
0
-1e
NA
He nucleus
electron
EM energy
Atomic number
2
-1
NA
Mass number
4
0
NA
Relative mass
4
1/
1837
NA
Greek Letter
Symbol
Actually is…
Relative charge
Penetrating
Shielding
Nuclear Properties Table
Property
Alpha
Beta
Gamma



4
2He
0
-1e
NA
He nucleus
electron
EM energy
Atomic number
2
-1
NA
Mass number
4
0
NA
Relative mass
4
1/
1837
NA
+2
-1
NA
Greek Letter
Symbol
Actually is…
Relative charge
Penetrating
Shielding
Nuclear Properties Table
Property
Alpha
Beta
Gamma



4
2He
0
-1e
NA
He nucleus
electron
EM energy
Atomic number
2
-1
NA
Mass number
4
0
NA
Relative mass
4
1/
1837
NA
+2
-1
NA
Low
Medium
High
Greek Letter
Symbol
Actually is…
Relative charge
Penetrating
Shielding
Nuclear Properties Table
Property
Alpha
Beta
Gamma



4
2He
0
-1e
NA
He nucleus
electron
EM energy
Atomic number
2
-1
NA
Mass number
4
0
NA
Relative mass
4
1/
1837
NA
+2
-1
NA
Low
Medium
High
2.5 cm of air;
anything else
Metal, plastic
or wood
Lead or
concrete
Greek Letter
Symbol
Actually is…
Relative charge
Penetrating
Shielding