Nuclear ChemistryNuclear Chemistry

The study of The study of changes to the changes to the nucleus of the nucleus of the

atom.atom.

The NucleusThe Nucleus

Comprised of protons and neutrons (Comprised of protons and neutrons (nucleonsnucleons).).

# protons = atomic number.# protons = atomic number.

# protons + neutrons = mass number# protons + neutrons = mass number

Isotope ReviewIsotope ReviewIsotopeIsotope: :

Atoms of the same element with Atoms of the same element with different numbers of different numbers of neutronsneutrons. .

Have different levels of “Have different levels of “abundanceabundance” in nature.” in nature.

Some isotopes or “Some isotopes or “nuclidesnuclides” of an element can be ” of an element can be unstable, or “unstable, or “radioactiveradioactive”.”.

Note: We will be talking about isotopes very specifically Note: We will be talking about isotopes very specifically in this unit. We will not be using the average atomic in this unit. We will not be using the average atomic mass you see on the Ref tables. mass you see on the Ref tables.

What is Radioactivity?What is Radioactivity?

Radioactivity:Radioactivity: the “ the “decaydecay” of the nucleus ” of the nucleus by emitting particles and/or energy in order by emitting particles and/or energy in order to become more stable.to become more stable.

What Causes an Isotope to be What Causes an Isotope to be Radioactive and Decay?Radioactive and Decay?

Proton : Neutron

ratio in nucleus

Neutron-Proton RatiosNeutron-Proton Ratios

Positive protons in the Positive protons in the nucleus repel each other.nucleus repel each other.

Neutrons play a key role Neutrons play a key role stabilizing the nucleus.stabilizing the nucleus.

Neutron-Proton RatiosNeutron-Proton Ratios

For smaller nuclei For smaller nuclei (atomic # below 20) (atomic # below 20) stable nuclei have a stable nuclei have a neutron-to-proton neutron-to-proton ratio close to 1:1.ratio close to 1:1.

Neutron-Proton RatiosNeutron-Proton Ratios

As nuclei get As nuclei get larger, it takes a larger, it takes a greater number of greater number of neutrons to neutrons to stabilize the stabilize the nucleus.nucleus.

Stable NucleiStable Nuclei

There are no stable nuclei with an There are no stable nuclei with an atomic number greater than 83.atomic number greater than 83.

Types ofTypes ofRadioactive DecayRadioactive Decay

http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/radioa7.swf

Early Pioneers in RadioactivityEarly Pioneers in Radioactivity

Roentgen:

Discoverer of X-rays 1895

Becquerel:

Discoverer of Radioactivity

1896

The Curies:

Discoverers of Radium and

Polonium 1900-1908

Rutherford:

Discoverer Alpha and Beta

rays 1897

Ernest Rutherford discovered three types of radioactive emissions by using a magnetic field.

Reference Table OReference Table O

Shows the symbols Shows the symbols of some of the of some of the different particles different particles used in nuclear used in nuclear chemistry.chemistry.

Top # = massTop # = mass Bottom # = chargeBottom # = charge

Alpha DecayAlpha Decay

An An -particle is emitted (basically a helium nucleus)-particle is emitted (basically a helium nucleus)

He42

U23892

Th23490 He4

2+

Heaviest type of Heaviest type of emissionemission

Mass of 4Mass of 4Charge of +2Charge of +2

Beta DecayBeta Decay

A A -- particle is emitted (a high energy electron) particle is emitted (a high energy electron)

0−1 e0

−1or

I13153 Xe131

54 + e0

−1

Wait a ticWait a tic How does a nucleus How does a nucleus

give off an electron!give off an electron!

Neutron splits into a Neutron splits into a proton and electron.proton and electron.

n n → p→ p++ + e + e--

Proton stays behind Proton stays behind and electron shoots and electron shoots out of nucleus.out of nucleus.

Positron EmissionPositron Emission

A positron is emitted (a particle that has A positron is emitted (a particle that has the same mass as but opposite charge the same mass as but opposite charge than an electron)than an electron)

e0+1

C116

B115 + e0

+1

Positrons are a Positrons are a type of type of ““antimatterantimatter”.”.

Quickly destroyed Quickly destroyed as soon as they as soon as they come in contact come in contact with an electron.with an electron.

Gamma EmissionGamma Emission

High-energy radiation that almost always High-energy radiation that almost always accompanies the loss of a nuclear particle.accompanies the loss of a nuclear particle.

It is It is NOT a particleNOT a particle, it is pure energy., it is pure energy.No mass or charge.No mass or charge.Not affected by a magnetic field.Not affected by a magnetic field.

00

Don’t make me mad…Don’t make me mad…

Ms. Nelson on a bad day…

Electron CaptureElectron Capture

An electron close toAn electron close to

nucleus get “captured’.nucleus get “captured’.

It combines with aIt combines with a

proton to make a neutron.proton to make a neutron.

p11 + e0

−1 n1

0

Penetrating PowerPenetrating Power Penetrating Power:Penetrating Power:

how far radiation can how far radiation can travel through travel through material. material.

Protection requires Protection requires different degrees of different degrees of shieldingshielding..

Alpha – paper or skinAlpha – paper or skinBeta – aluminum foilBeta – aluminum foilGamma – thick leadGamma – thick lead

Ionizing Ability:Ionizing Ability: how well how well radiation strips electrons radiation strips electrons from other atoms and from other atoms and molecules creating ions.molecules creating ions. Can cause mutations, and cell Can cause mutations, and cell

destructiondestruction

Alpha - HighestAlpha - Highest Beta - MiddleBeta - Middle Gamma – LowGamma – Low

Ionizing AbilityIonizing Ability

Damage to CellsDamage to Cells

Because of high ionizing Because of high ionizing ability, Alpha and Beta ability, Alpha and Beta cause most damage cause most damage inside the human body.inside the human body.

Gamma rays are less Gamma rays are less ionizingionizing but protection but protection against gammas against gammas requires thicker requires thicker shielding. shielding.

Measuring RadioactivityMeasuring Radioactivity One can use a device like a One can use a device like a Geiger counterGeiger counter to to

measure the amount of activity present in a measure the amount of activity present in a radioactive sample.radioactive sample.

Natural Transmutation (Decay)Natural Transmutation (Decay)

Spontaneous transmutation of a radioisotope Spontaneous transmutation of a radioisotope into another element.into another element.

Doesn’t require the input of outside energy.Doesn’t require the input of outside energy.Occurs at a specific rate that we can Occurs at a specific rate that we can

measure. (measure. (Half LifeHalf Life))

Artificial TransmutationArtificial Transmutation The change of one element to another artificially by The change of one element to another artificially by bombardingbombarding it with it with

other particles.other particles.

These equations always have 2 reactants on the left (as opposed to These equations always have 2 reactants on the left (as opposed to natural decay)natural decay)

Artificial Transmutation Natural Transmutation

How do We Bombard Nuclei?How do We Bombard Nuclei?

Particle Accelerators:Particle Accelerators:Speed up Speed up charged charged particles particles in a in a magnetic fieldmagnetic field to collide to collidewith nucleiwith nuclei

Neutrons and gamma radiation Neutrons and gamma radiation can’t be acceleratedcan’t be accelerated as they as theyhave no charge!have no charge!

Typical Particle AcceleratorTypical Particle Accelerator

Enormous, with circular tracks with radii that Enormous, with circular tracks with radii that are miles long.are miles long.

Brookhaven AcceleratorBrookhaven Accelerator

Balancing Nuclear EquationsBalancing Nuclear Equations

Mass and charge Mass and charge are “conserved”are “conserved”

Balance so that the Balance so that the mass (top #’s) and mass (top #’s) and charge (bottom #’s) charge (bottom #’s) equal each other.equal each other.

Typical Test QuestionsTypical Test Questions

Radioactive SeriesRadioactive Series

Decay Series:Decay Series: very large very large radioactive nuclei radioactive nuclei undergo a “series” of undergo a “series” of decays until they form a decays until they form a stable nuclide (often a stable nuclide (often a nuclide of lead).nuclide of lead).

Transuranium ElementsTransuranium Elements: : Elements “beyond” uranium (largest natural element)Elements “beyond” uranium (largest natural element) Atomic numbers greater than 92Atomic numbers greater than 92 Artificially createdArtificially created through nuclear bombardment through nuclear bombardment

Video: Video: Islands of Stability (13 minutes)Islands of Stability (13 minutes)http://www.youtube.com/watch?v=woPx-Ex7H8A&safe=activehttp://www.youtube.com/watch?v=woPx-Ex7H8A&safe=active

Half LifeHalf Life

Amount of time for half a radioactive sample to Amount of time for half a radioactive sample to decay.decay.

Length of a half life Length of a half life cannot be changed.cannot be changed.

Ranges from milliseconds to billions of years. Ranges from milliseconds to billions of years. (See Table N)(See Table N)

Radioactivity decreases with time.Radioactivity decreases with time.

Radioactive DatingRadioactive Dating Rate of decay is constant over Rate of decay is constant over

time.time.

Measure amount of Measure amount of radioisotope remaining in radioisotope remaining in sample to determine age.sample to determine age.

C-14 is used to date organic C-14 is used to date organic material up to 60,000 years material up to 60,000 years old.old.

U-238 is used to date U-238 is used to date extremely old geological extremely old geological formationsformations

Carbon 14 Dating:n (2 minutes)Carbon 14 Dating:n (2 minutes) http://www.youtube.com/watch?v=31-P9pcPStg&safe=activehttp://www.youtube.com/watch?v=31-P9pcPStg&safe=active

Reference Table NReference Table N

Decay mode:Decay mode: type of type of particle emitted by natural particle emitted by natural decaydecay

Half Life:Half Life: length of time for length of time for “half” of the atoms in a “half” of the atoms in a sample to undergo natural sample to undergo natural decay.decay.

Half Life Formula:Half Life Formula:

# Half Lives = # Half Lives = Total Time ElapsedTotal Time Elapsed Time of One Half Time of One Half

Life (Life (tt1/21/2 ) )

Half Life ProblemHalf Life Problem

Ex: Ex: If 500 grams of I-131, tIf 500 grams of I-131, t1/21/2 = 8 days, = 8 days,

decays for 32 days, how much decays for 32 days, how much would remain?would remain?

32 days32 days = 4 half lives = 4 half lives

8 days8 days

500 g 500 g → 250 g→ 125 g → 62.5 g→ → 250 g→ 125 g → 62.5 g→ 31.25 grams31.25 grams

Half Life ProblemHalf Life Problem

Ex: Ex: If 300g of a radioisotope decays to If 300g of a radioisotope decays to 37.5g in 120 days, what is the t37.5g in 120 days, what is the t1/21/2 ? ?

300 300 → 150 → 75 → 37.5g→ 150 → 75 → 37.5g3 half lives3 half lives

3 half lives = 3 half lives = 120 days120 days tt1/2 1/2 = 40 days= 40 days

tt1/21/2

Half Life ProblemHalf Life Problem

Ex: Ex: What fraction of a sample of I-131 What fraction of a sample of I-131 remains after 24 days of decay? remains after 24 days of decay?

tt1/21/2 = 8 days = 8 days

24 days24 days = 3 half lives = 3 half lives 8 days8 days

StartStart End End

1 1 → ½ → ¼ → → ½ → ¼ → 1/81/8

Half Life ProblemHalf Life Problem

Ex: Ex: If 60 g of N-16 remains in a If 60 g of N-16 remains in a sample. How many grams were sample. How many grams were present 28 seconds ago? present 28 seconds ago?

tt1/21/2 = 7 sec. = 7 sec.

28 sec28 sec = 4 half lives = 4 half lives AGOAGO7 sec7 sec

We double going back in timeWe double going back in time 60 60 → 120 → 240 → 480 → → 120 → 240 → 480 → 960 grams960 grams

Use the graph to see how much time it takes for half the nuclei to decay

Half Life Half Life GraphGraph

http://www.colorado.edu/physics/http://www.colorado.edu/physics/2000/isotopes/2000/isotopes/radioactive_decay3.htmlradioactive_decay3.html

Energy in Nuclear ReactionsEnergy in Nuclear Reactions Nuclear reactions yield more Nuclear reactions yield more

energy than chemical reactionsenergy than chemical reactions

When changes happen to the When changes happen to the nucleus, some nucleus, some matter is matter is converted to energyconverted to energy..

Einstein’s famous equation, Einstein’s famous equation,

EE = = mcmc22, allows us to calculate , allows us to calculate this energy.this energy.

Energy in Nuclear ReactionsEnergy in Nuclear Reactions

E = energy in JoulesE = energy in Joulesm = mass (lost) in kilogramsm = mass (lost) in kilogramsc = the speed of light (3 x 10c = the speed of light (3 x 1088 meters/sec) meters/sec)

Energy in Nuclear ReactionsEnergy in Nuclear Reactions

Ex: Ex: The The mass changemass change for the decay of for the decay of

1 mole of uranium-238 is 0.0046 g.1 mole of uranium-238 is 0.0046 g.

The change in energy, The change in energy, EE, is then, is then

EE = ( = (mm) ) cc22

EE = (4.6 = (4.6 10 10−−66 kg)(3.00 kg)(3.00 10 1088 m/s) m/s)22

EE = 4.1 = 4.1 10 101111 Joules Joules

Mass Defect (Honors)Mass Defect (Honors)The difference between the mass of an The difference between the mass of an

atom and the sum of the masses of the atom and the sum of the masses of the individual protons and neutrons in it’s individual protons and neutrons in it’s nucleus. nucleus.

The "vanishing" mass The "vanishing" mass of the protons and neutrons of the protons and neutrons is converted to energy. is converted to energy.

Nuclear Fission = Nuclear Fission = Splitting the NucleusSplitting the Nucleus

Nuclear FissionNuclear Fission

Large nuclei are split (basically Large nuclei are split (basically in half), producing various in half), producing various “fission products” and large “fission products” and large amounts of energy.amounts of energy.

Total mass after splitting is less Total mass after splitting is less than what you started with.than what you started with.

Matter is converted to energy.Matter is converted to energy.

http://www.montereyinstitute.org/courses/Environmental%20Science/course%20files/http://www.montereyinstitute.org/courses/Environmental%20Science/course%20files/multimedia/lesson02/animations/2a_Nuclear_Fission.htmlmultimedia/lesson02/animations/2a_Nuclear_Fission.html

Recognize this ReactionRecognize this Reaction

http://www.youtube.com/watch?v=T5g85zIDcec&safe=active

Nuclear Chain ReactionNuclear Chain Reaction::Bombard nuclide with a neutron.Bombard nuclide with a neutron.Nuclei split releasing more neutrons that Nuclei split releasing more neutrons that

strike other nuclei, and so on and so on....strike other nuclei, and so on and so on....

Critical Mass: minimum amount of fissionableminimum amount of fissionable

material present for the chain reaction to be sustained.material present for the chain reaction to be sustained.

Controlled vs. Uncontrolled FissionControlled vs. Uncontrolled Fission

Controlled Chain ReactionControlled Chain Reaction: occurs in : occurs in nuclear reactors or power plants.nuclear reactors or power plants.Some of the free neutrons are removed Some of the free neutrons are removed

Uncontrolled Chain Reaction:Uncontrolled Chain Reaction: occurs in occurs in nuclear bombs or “atomic bombs”.nuclear bombs or “atomic bombs”.

Video Clip:Video Clip:

Uncontrolled FissionUncontrolled Fission

http://www.youtube.com/watch?v=DmSC_Or5y3Q&safe=activehttp://www.youtube.com/watch?v=DmSC_Or5y3Q&safe=active

Nuclear Power PlantsNuclear Power Plants

Nuclear ReactorNuclear ReactorGenerates heat through Generates heat through controlled controlled nuclear nuclear fission to produce steam that turns a turbine fission to produce steam that turns a turbine connected to an electric generator.connected to an electric generator.

Major Parts of a Nuclear ReactorMajor Parts of a Nuclear Reactor Fuel Rods:Fuel Rods:

Contain a fissionable isotope Contain a fissionable isotope Surrounded by coolant in the reactor coreSurrounded by coolant in the reactor core

Enriched U-235, Pu-239Enriched U-235, Pu-239

Moderator:Moderator: Slows downSlows down neutrons to increase neutrons to increase

chances for fission.chances for fission.Graphite, water, or heavy waterGraphite, water, or heavy water

Control Rods:Control Rods: Absorb excessAbsorb excess neutrons neutrons Control rate of chain reaction (can be Control rate of chain reaction (can be

raised and lowered)raised and lowered)Boron or CadmiumBoron or Cadmium

Coolant:Coolant: Stops core from overheatingStops core from overheating Transfers heat to heat exchangerTransfers heat to heat exchanger

Water, air, heavy waterWater, air, heavy water

Shielding:Shielding: Steel reinforced concrete to protect workers from Steel reinforced concrete to protect workers from

radiationradiation

Heat Exchanger:Heat Exchanger: Heat from fission is transferred to water which turns to Heat from fission is transferred to water which turns to

steamsteam

Turbine:Turbine: Steam generates electricity Steam generates electricity

How a Nuclear Reactor Works:

http://www.youtube.com/watch?v=LTnfXLws40Q&feature=related&safety_mode=true&persist_safety_mode=1&safe=active

Breeder ReactorsBreeder Reactors

Use U-238, a nonfissionable but much Use U-238, a nonfissionable but much more plentiful isotope of uranium (99%).more plentiful isotope of uranium (99%).

It undergoes transmutation into Pu-239 a It undergoes transmutation into Pu-239 a fissionable isotope of plutoniumfissionable isotope of plutonium

Nuclear Power Nuclear Power supplies about supplies about 20% of the 20% of the country’s country’s electric powerelectric power

Pros & Cons of Nuclear PowerPros & Cons of Nuclear Power

ProsPros

What is positive about using nuclear What is positive about using nuclear fission as a source of energy?fission as a source of energy?

Large amount of energy from very small Large amount of energy from very small quantity of fuel.quantity of fuel.

No greenhouse gas is produced (CONo greenhouse gas is produced (CO22))

Less reliance on foreign countries for fuel.Less reliance on foreign countries for fuel.

ConsCons

What are some of the negative aspects of What are some of the negative aspects of using nuclear fission as a source of using nuclear fission as a source of energy?energy?

Exposure to Radiation

Effects of Radiation ExposureEffects of Radiation Exposure

Somatic Effects:Somatic Effects: Kills body cells or makes them cancerous.Kills body cells or makes them cancerous. ““Radiation sickness” (hair falls out, nausea, Radiation sickness” (hair falls out, nausea,

fatigue, radiation “burns”)fatigue, radiation “burns”)

Genetic EffectsGenetic Effects: : Mutations in eggs and sperm increase chance Mutations in eggs and sperm increase chance

of mutations in next generation.of mutations in next generation.

Effects of Radiation ExposureEffects of Radiation Exposure

Note:Note: Chemical properties of radioisotopesChemical properties of radioisotopesare the same as nonradioactive.are the same as nonradioactive.

Can get incorporated into bone, tissueCan get incorporated into bone, tissueand organs for a long time.and organs for a long time.

Ex: Sr-90 is chemically similar to CalciumEx: Sr-90 is chemically similar to Calcium

Nuclear Reactor Malfunctions

Three Mile Island,Three Mile Island,PA (1979)PA (1979)

(Worst accident in (Worst accident in U.S. nuclear power U.S. nuclear power plant history.plant history.

Released moderate Released moderate amounts of amounts of radioactive gases radioactive gases into the into the environmentenvironment ) )

Chernobyl, Ukraine (1986)

Video:

http://youtu.be/BfKm0XXfiis

FukashimaFukashima, ,

Japan (2011)Japan (2011)

“Nuclear Boy Cartoon” http://www.youtube.com/watch?v=45gxTXgvK50&safety_mode=true&persist_safety_mode=1&safe=active

Long-term Storage of

Radioactive Wastes

((JUST READ)JUST READ) Since the 1940s, the United States has Since the 1940s, the United States has

generated over 75,000 metric tons of spent generated over 75,000 metric tons of spent nuclear fuel and high-level nuclear waste at 80 nuclear fuel and high-level nuclear waste at 80 sites in 35 states. sites in 35 states.

That’s enough to fill That’s enough to fill

a football field about a football field about

15 feet deep.15 feet deep.

Nuclear waste is expected to increase by about Nuclear waste is expected to increase by about 2,000 metric tons per year, more than doubling 2,000 metric tons per year, more than doubling to 153,000 metric tons by 2055. to 153,000 metric tons by 2055.

The closest we’ve come to The closest we’ve come to a long term nuclear-waste a long term nuclear-waste storage has been Yucca storage has been Yucca Mountain: a “geological Mountain: a “geological repository,” site about 100 repository,” site about 100 miles Northwest of Las miles Northwest of Las Vegas.Vegas.

Nuclear Fusion = Nuclear Fusion = Joining Nuclei TogetherJoining Nuclei Together

Nuclear FusionNuclear Fusion

Nuclear FusionNuclear Fusion: the joining together of : the joining together of smaller nuclei to make larger ones.smaller nuclei to make larger ones.

Recognize this Type of EquationRecognize this Type of Equation

Fission Vs. FusionFission Vs. Fusion

It’s Really Hard to do!It’s Really Hard to do!

Due to the Due to the repulsive forces between repulsive forces between positive nucleipositive nuclei, this requires extremely , this requires extremely high temp. and pressures.high temp. and pressures.

Stars = Fusion ReactorsStars = Fusion Reactors Stars generate Stars generate

energy through energy through fusion.fusion.

All elements in the All elements in the universe were formed universe were formed through the process through the process of fusion.of fusion.

Video: Video: How elements are formedHow elements are formed

http://youtu.be/neMEo8ZrwuIhttp://youtu.be/neMEo8ZrwuI

Nuclear FusionNuclear Fusion

ProsProsProduces more energy than fission.Produces more energy than fission.Fuel (hydrogen) is plentifulFuel (hydrogen) is plentifulNo radioactive wasteNo radioactive waste

ConsConsHigh temp./pressure needed to initiate.High temp./pressure needed to initiate.Material must be in the Material must be in the plasmaplasma state state

at several million kelvins.at several million kelvins.No fusion reactors exist, still in No fusion reactors exist, still in

research stage.research stage.

Nuclear Fusion (just read)Nuclear Fusion (just read)

Tokamak apparati like the Tokamak apparati like the one shown at the right one shown at the right show promise for carrying show promise for carrying out these reactions.out these reactions.

They use magnetic fields They use magnetic fields to heat the material.to heat the material.

Visual Ex:Visual Ex:

Tokamak Fusion ReactorTokamak Fusion Reactorhttp://www.visionlearning.com/library/flash_viewer.php?oid=2747http://www.visionlearning.com/library/flash_viewer.php?oid=2747

Hydrogen “Fusion” BombHydrogen “Fusion” Bomb

Thermonuclear Bomb:

A fission bomb explodes, providing the heat and pressure necessary for fusion to occur.

Much more destructive than an atomic “fission” bomb

Otherwise known as “Dabomb”

Beneficial Uses of RadiationBeneficial Uses of Radiation

Dating MaterialsDating Materials

Half Lives don’t change!Half Lives don’t change!

Carbon-14:Carbon-14: date organic materials date organic materials

Uranium-238Uranium-238: date extremely old : date extremely old geological formations (very long half life)geological formations (very long half life)

Non-Invasive Body ImagingNon-Invasive Body Imaging

RadioactiveRadioactive

material injected material injected

Radiation detectedRadiation detected

to give imageto give image

Used to:Used to:Locate tumorsLocate tumors

Determine organDetermine organ

functionfunction

Skeletal Scan of Person After a Tc-99m Injection

Cancer TreatmentCancer Treatment

Direct Direct external external radiation beam at tumor, radiation beam at tumor, usually from Co-60 gamma radiation.usually from Co-60 gamma radiation.

InternallyInternally deposit “seeds” containing deposit “seeds” containing radioactive materials near tumor site.radioactive materials near tumor site.

Therapy Machine used for Targeting Cancerous Tissue

Important!!!Important!!!

Isotopes used in medical diagnosis and Isotopes used in medical diagnosis and treatment should always have:treatment should always have:

SHORT HALF LIVESSHORT HALF LIVES

BE QUICKLY ELIMINATED FROM THE BODYBE QUICKLY ELIMINATED FROM THE BODY

Some Isotopes Used in MedicineSome Isotopes Used in MedicineImportant.Important.

I-131I-131: treat and diagnosis thyroid disorders: treat and diagnosis thyroid disorders

Co-60Co-60: emits gamma radiation to treat cancer: emits gamma radiation to treat cancer

Tc-99Tc-99: treats brain tumors: treats brain tumors

Th-201Th-201: useful to study damage to the heart: useful to study damage to the heart

Tracers:Tracers:

Radioisotopes react chemically the same way as Radioisotopes react chemically the same way as nonradioactive (same # valence electrons).nonradioactive (same # valence electrons).

Use them to “trace” the path of a chemical through Use them to “trace” the path of a chemical through the body or through a chemical reaction mechanism.the body or through a chemical reaction mechanism.

Ex: C-14, P-32, O-18Ex: C-14, P-32, O-18

Sterilization:Sterilization:

Gamma rays kill bacteria, mold, fungus on surface.Gamma rays kill bacteria, mold, fungus on surface.

Medical instruments Medical instruments

Food (ground beef, strawberries, etc.)Food (ground beef, strawberries, etc.)gives food a longer shelf-lifegives food a longer shelf-lifeprevents E-coli outbreaks prevents E-coli outbreaks Controls sproutingControls sproutingDoes not make the food radioactiveDoes not make the food radioactiveFDA ApprovedFDA Approved

Spacecraft Power SuppliesSpacecraft Power Supplies

Have allowed space craft to explore the Have allowed space craft to explore the outer solar system, too far from the sun for outer solar system, too far from the sun for solar panels to be effectivesolar panels to be effective

The EndThe End