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ASSIGNMENTS
1.) Read p.292-297 (Radioactivity)2.) Complete “Types of Radiation” WS
(Chap 10.1 Reading Organizer)3.) p.297 Assessment Questions 1-9
Radioactivity
NotesTim F. Rowbotham 2010
Radioactivity
Intro Video
“Final Above Ground Atomic Tests”
Nuclear Stability
In the nucleus, protons and neutrons are held together by the strong nuclear force. It overcomes the weaker electric force of repulsion.
Nuclear Instability
But some atoms have unstable
nuclei. The strong force is not great
enough.
Their nuclei have a tendency to “fall apart” a bit due to this instability.
Nuclear Radiation
Unstable nuclei will jettison
some particles or energy in
order to become more
stable.
Nuclear Radiation
The particles or energy ejected from the nucleus of an atom is what
we call nuclear radiation.
Radioactive Elements
Radioactive elements are those atoms that have unstable nuclei,
thus would eject particles or energy from their nuclei.
They are called radioactive isotopes, or radioisotopes for short.
Radioactive Decay
When an atom gives off nuclear radiation, we call the process
radioactivity or nuclear decay.During nuclear decay, an atom may
change into an entirely new element.(Remember, the number of protons is what determines the type of atom.)
Learning Check
READY YOUR REMOTE
What causes radioactivity?
0%
0%
0%
0% 1. A chemical reaction
2. An unstable nucleus
3. The earth’s magnetic field
4. The jet stream
An element that gives off radiation is called
0%
0%
0%
0% 1. an ion
2. a molecule
3. an isotope
4. a radioisotope
Radioactivity
Video Clip - Radioactivity
Nuclear Decay Products
Through nuclear decay, an element can change to another element, so
we refer to the initial radioisotope as the parent and the element it
becomes as the daughter product.
PARENT Radiation + DAUGHTER
Parent & Daughter Elements
Sample Parent & Daughters
PARENT Radiation + DAUGHTER Ra-226 α + Rn-222 U-238 α + Th-234 Th-234 β + Pa-234 C-14 β + N-14 K-42 β + Ar-42
Learning Check
READY YOUR REMOTE
The new element formed after the decay of the radioisotope is referred to as the
0%
0%
0%
0% 1. Parent element
2. Daughter element
3. Created element
4. Nuclear element
The radioisotope giving off radiation is referred to as the
0%
0%
0%
0% 1. Parent element
2. Daughter element
3. Created element
4. Nuclear element
Types of Nuclear Radiation
There are 3 common types of nuclear radiation:
ALPHA PARTICLES
BETA PARTICLES
GAMMA RAYS
Alpha Decay
In alpha decay, an alpha particle is released from the nucleus.
An alpha particle is 2 protons attached to 2 neutrons.
It is the same as a helium nucleus.
Alpha Decay
education.jlab.org/glossary/alphadecay.htm
Alpha Decay
http://santasusana.org/pakelly/G%20Chemistry/changes_in_the_nucleus.htm
Alpha Decay
http://www.umich.edu/~radinfo/introduction/lesson/alpha.htm
Alpha Decay
http://www.hk-phy.org/resources/images/atomic01/?N=A
Quick Review
READY YOUR REMOTE
What does an alpha particle consist of?
0%
0%
0%
0% 1. An electron
2. A proton
3. A proton & a neutron
4. 2 protons & 2 neutrons
What causes radioactivity?
0%
0%
0%
0% 1. A chemical reaction
2. An unstable nucleus
3. The earth’s magnetic field
4. The jet stream
The new element formed after the decay of the radioisotope is referred to as the
0%
0%
0%
0% 1. Parent element
2. Daughter element
3. Created element
4. Nuclear element
ASSIGNMENTS
1.) RETURN REMOTE2.) Complete PACKET pages 10-11 “Radioactive Elements”3.) Video: The Manhattan Project
VIDEO
Video: The Manhattan Project
Quick Review
READY YOUR REMOTE
The new element formed after the decay of the radioisotope is referred to as the
0%
0%
0%
0% 1. Parent element
2. Daughter element
3. Created element
4. Nuclear element
What causes radioactivity?
0%
0%
0%
0% 1. A chemical reaction
2. An unstable nucleus
3. The earth’s magnetic field
4. The jet stream
An element that gives off radiation is called
0%
0%
0%
0% 1. a radioisotope
2. an ion
3. a molecule
4. an isotope
Quick Review
1.) VIDEO CLIP – Atomic Bomb2.) Turn to page 3 of your notes
Beta Decay
In beta decay, a beta particle is released from the nucleus.
A beta particle is really an electron.
During beta decay, a neutron changes into a proton and electron.
The proton stays and the electron is jettisoned from the nucleus.
Beta Decay
education.jlab.org/glossary/betadecay.htm
Beta Decay
http://santasusana.org/pakelly/G%20Chemistry/changes_in_the_nucleus.htm
Beta Decay
http://www.hk-phy.org/resources/images/atomic01/?N=A
What is a beta particle?
0%
0%
0%
0% 1. An electron
2. A proton
3. A proton & a neutron
4. 2 protons & 2 neutrons
Gamma Decay
In gamma decay, no particle is released by the nucleus – only
energy!!Gamma decay, by itself, does not
change the atom into a new element.Gamma decay often accompanies
alpha or beta decay.
Gamma Decay
http://santasusana.org/pakelly/G%20Chemistry/Gammae.gif
Gamma Decay
http://www.umanitoba.ca/faculties/medicine/radiology/stafflist/staffitems/RADPRO%20Course/radiation.htm
Gamma Decay
http://www.odec.ca/projects/2007/pete7o2/Background.html
http://www.newworldencyclopedia.org/entry/Gamma_ray
Quick Review
READY REMOTES
What does an alpha particle consist of?
0%
0%
0%
0% 1. An electron
2. A proton
3. A proton & a neutron
4. 2 protons & 2 neutrons
What does a beta particle consist of?
0%
0%
0%
0% 1. An electron
2. A proton
3. A proton & a neutron
4. 2 protons & 2 neutrons
ASSIGNMENTS
1.) RETURN REMOTE2.) All About Radiation Worksheet
ASSIGNMENTS
1.) Radioactivity Quiz2.) All About Radiation Worksheet3.) Video: Atomic Bomb – The End
Nuclear Decay Equations
Radiation Penetration
How to block
Paper
Thin sheet of metal
3 ft of concrete
3 in of lead
TYPEALPHA PARTICLE BETA PARTICLE
GAMMA RAY
or
The types of nuclear radiation have differing abilities to penetrate matter.
Radiation Penetration
Radiation Penetration
Effects of Radiation
Radiation that occurs naturally every day is called background
radiation.Nuclear radiation can ionize atoms – breaking apart the chemical bonds that hold
molecules together.
Effects of Radiation
Detecting Radiation
One device that detects ionizing radiation is called a Geiger counter.
What is necessary to block a gamma ray?
0%
0%
0%
0% 1. A piece of paper
2. A piece of metal
3. 3 inches of concrete
4. 3 feet of concrete
ASSIGNMENTS
1.) RETURN REMOTE2.) PACKET page 12 – 15 (Nuclear Decay Eqns)
3.) Video: Devastating Radiation
CIVIL DEFENSE
Video – Duck & Cover
QUICK REVIEW & PRACTICE
1.) Take out your periodic table2.) READY YOUR REMOTE
What is the mass of an alpha particle?
0%
0%
0%
0% 1. 0 amu
2. 1 amu
3. 2 amu
4. 4 amu
When polonium-218 undergoes alpha decay, what daughter element is produced?
0%
0%
0%
0% 1. Astatine-218
2. Radon-222
3. Lead-214
4. Bismuth-216
When protactinium-234 undergoes beta decay, what daughter element is produced?
0%
0%
0%
0% 1. Uranium-234
2. Neptunium-238
3. Actinium-230
4. Thorium-230
What isotope is produced as a result of the alpha decay of uranium-234?
0%
0%
0%
0% 1. Plutonium-238
2. Neptunium-238
3. Actinium-230
4. Thorium-230
QUICK REVIEW & PRACTICE
1.) Take out your periodic table2.) READY YOUR REMOTE
What is the mass of a beta particle?
0%
0%
0%
0% 1. 0 amu
2. 1 amu
3. 2 amu
4. 4 amu
When uranium-238 undergoes alpha decay, what daughter element is produced?
0%
0%
0%
0% 1. Uranium-234
2. Neptunium-238
3. Actinium-230
4. Thorium-234
What isotope is produced as a result of the beta decay of carbon-14?
0%
0%
0%
0% 1. Boron-14
2. Carbon-12
3. Nitrogen-14
4. Beryllium-10
ASSIGNMENTS
VIDEO – Nuclear Power
NOTES
p.6-7 Half-Life
Rate of Nuclear Decay
It is not possible to predict exactly when a particular radioactive atom
will emit radiation.However, it is possible to know how
many will decay over a certain amount of time.
Half-Life
A half-life is the amount of time it takes for half of sample of the parent to
decay.(If you start with 100 atoms, it’s the
time it takes for 50 to decay.)This time differs depending on the
radioisotope.
Half-Life
The number of atoms is cut in half once for every half-life.
Half-Life
ionactive.co.uk
Half-Life
Every half-life, one half of the parent isotope remaining becomes the daughter element.
Half-Life
Half-Life
www.datamentor.org
If we start with 24 radioactive atoms...
How many are left after 1 half-life?
after 2 half-lives?
Half-Life of 3 Hours
http://ohioline.osu.edu/rer-fact/rer_20.html
500 atoms after 1 half-life.
250 atoms after 2 half-lives.
125 atoms after 3 half-lives.
Half-Life of 3 Hours
http://ohioline.osu.edu/rer-fact/rer_20.html
6 hours = 2 half-lives.
9 hours = 3 half-lives.
12 hours = 4 half-lives.
Sample Half-Lives
RADIOISOTOPE
Potassium-37
Hydrogen-3
Carbon-14
Radium-226
Uranium-238
HALF-LIFE
1.23 seconds
12.26 years
5730 years
1600 years4,500,000,000 yrs
If you begin with 100 atoms of a radioisotope, how many would be left after 2 half-lives?
0%
0%
0%
0% 1. 100
2. 50
3. 25
4. 0
If its half-life was 10 minutes, how long would it take for a radioisotope to decay from 100 to 25?
0%
0%
0%
0% 1. 10 min
2. 20 min
3. 30 min
4. 40 min
ASSIGNMENTS
1.) RETURN REMOTE2.) Pick up a copy of the Radioactive Decay of Candium WS3.) Complete the Simulating Radioactive Decay WS (Graph)4.) Prepare for Candium Directions5.) Radioactive Decay & Half-Lives
QUICK REVIEW & PRACTICE
1.) Take out your periodic table2.) READY YOUR REMOTE
Phosphorus-32 decays by beta decay into what element?
0%
0%
0%
0% 1. Sulfur-32
2. Silicon-32
3. Aluminum-30
4. Argon-34
What is the mass of a beta particle?
0%
0%
0%
0% 1. 0 amu
2. 1 amu
3. 2 amu
4. 4 amu
If you begin with 40 atoms of a radioisotope, how many would be left after 3 half-lives?
0%
0%
0%
0% 1. 5
2. 10
3. 20
4. 40
If you begin with 120 atoms of a radioisotope, how many would be left after 3 half-lives?
0%
0%
0%
0% 1. 60
2. 30
3. 15
4. 0
ASSIGNMENTS
1.) RETURN REMOTE2.) Pick up a copy of the Simulating Radioactive Decay WS3.) Get with a partner4.) Listen for Directions5.) p.301 Assessment ?’s 1 – 7
Radioactive Decay & Half-lives
Use the tables in the back of your Radioactivity packet to help you answer these questions
1.) How much Ra-226 would be left after decay of 5 half-lives of 800g?
2.) How much time would that take? (HL = 1600 y)
3.) How much strontium-90 would be left after 4 half-lives of decay of 2000g?
4.) How long would this take? (HL = 28.1y)
QUICK REVIEW & PRACTICE
1.) Take out your periodic table2.) READY YOUR REMOTE
Carbon-14 decays by beta decay into what element?
0%
0%
0%
0% 1. Nitrogen-14
2. Carbon-12
3. Oxygen-14
4. Beryllium-10
Radioactive Decay & Half-lives
Use the tables in the back of your Radioactivity packet to help you answer these questions
Mar 21, 2011
1.) How much Co-60 would be left after decay of 3 half-lives of 1000 atoms?
2.) How much time would that take?
2.) How much daughter would be left?
4.) How much Iodine-131 would be left after 4 half-lives of decay of 4000 atoms?
5.) How long would this take?
6.) I-131 decays by beta decay into what element?
NOTES
Turn to p. 7 Notes
Radioactive Dating
Since half-life is a fairly constant rate for each specific element, it is most often used for radioactive dating.
The most well-known type is radiocarbon dating which is often
referred to as carbon dating.
Transmutation
Transmutation is when one type of atom becomes a different type of
atom.
It can only happen through a change in the nucleus.
It is a nuclear change.
Artificial Transmutation
Scientists perform artificial transmutations by bombarding nuclei with protons, or neutrons, or alpha
particles.
Transuranium elements are created by artificial transmutation of smaller
elements.
Strong nuclear force
Protons and neutrons are held in the nucleus by the strong nuclear force.The strong force is greater than the
electric force. However, the electric force of
repulsion increases much more with the addition of subatomic particles.
Strong nuclear force
When the electric force of repulsion is greater than the strong force, the
atom emits radiation.
lbl.gov
What two forces in the nucleus determine whether or not an atom emits radiation?
0%
0%
0%
0% 1. Gravity & Electromagnetic force
2. Ionic & Covalent forces
3. Electromagnetic & Strong forces
4. String & Particle forces
Transmutation does not take place in which of the following nuclear processes?
0%
0%
0% 1. Alpha decay
2. Beta decay
3. Gamma decay
ASSIGNMENTS
1.) RETURN REMOTE2.) Pick up a copy of Half-Life & complete one side (Easy/Hard)3.) Complete p.16-17 of Packet “Nuclear Chemistry Half-Life Calculations”
QUICK REVIEW & PRACTICE
1.) Take out your periodic table2.) READY YOUR REMOTE
What is the mass of an alpha particle?
0%
0%
0%
0% 1. 0 amu
2. 1 amu
3. 2 amu
4. 4 amu
An alpha particle is ejected from the nucleus of an uranium-235 atom. What new element does it become?
0%
0%
0%
0% 1. Uranium-231
2. Thorium-231
3. Neptunium-235
4. Plutonium - 233
Fission
Fission is the splitting of an atomic nucleus into two smaller atoms.
Fission
al-zen.com
Fission
A lot of energy is produced when
this occurs.
http://library.thinkquest.org/C003730/index.php3?ID=18
How much?
E= mc2
Law of Conservation of Mass
In chemical reactions, matter can not be created or destroyed, but
can change form.
In nuclear reactions, however, matter can be converted to
energy.
Law of Conservation of Mass and Energy
This law is modified when dealing with nuclear reactions.
According to the law of conservation of mass and energy, the total amount of mass and energy
remains constant.
Mass-Energy Equation
How are mass and energy related?
E= mc2
c = the speed of light
c = 299,792,458 meters per second
Fission Chain Reaction
A lot of energy is produced from a fission reaction, however, just one atom has a tiny amount of mass so releases
little energy.
A chain reaction must be produced.
This happens when neutrons released during fission, hit and split other atoms.
Uses of Fission
Nuclear Weapons
http://www.adapage.com/magazzino/Photo%20Bombe%20Atomiche.htm
Uses of Fission
Nuclear Power
Fusion
Fusion is combining
two atoms to form a larger
nucleus.
http://mosaic.cnfolio.com/B101CW2007A166
alternativeenergyrevealed.com
Uses of Fusion
Fusion requires extremely high temperatures.
It occurs naturally in the
sun.
neoteo.com
Uses of Fusion
We can also produce fusion
in a thermonuclear weapon, which is even more
powerful.http://www.flickr.com/photos/7969902@N07/510672745/
In what type of nuclear reaction is the nucleus of an atom split?
0%
0%
0%
0% 1. Fission
2. Fusion
3. Gamma Decay
4. Ionic bonding
There are 800 atoms of a radioisotope. How many atoms would there be after 4 half-lives of decay?
0%
0%
0%
0% 1. 400
2. 200
3. 100
4. 50
The equation E = m c2 means what?
0%
0%
0%
0% 1. Energy can neither be created nor destroyed
2. Matter can be converted into energy
3. Everything is made out of matter
4. Chemical reactions release a lot of energy
ASSIGNMENTS
1.) RETURN REMOTE2.) Pick up a copy of Half-Lives / Nuclear Reaction WS & complete at least one side3.) Complete p.18-19 of Packet “Half-Life Worksheet”4.) Test tomorrow – Packets due!!
