2 - 1 CH 104 Chapter 3: Nuclear Chemistry Radioactivity Nuclear Equations Radiation Detection Half-Life Medical Applications Fission & Fusion.

2 - 1CH 104

Chapter 3: Nuclear ChemistryChapter 3: Nuclear Chemistry

RadioactivityRadioactivity

Nuclear EquationsNuclear EquationsRadiation DetectionRadiation Detection

Half-LifeHalf-Life

Medical ApplicationsMedical Applications

Fission & FusionFission & Fusion

2 - 2CH 104

Isotopes of HydrogenIsotopes of HydrogenIsotopes =Isotopes = Atoms of the same element but

having different masses.

11

21

31

H H H

++

--

++

--

++

--

Protium99.99%99.99%Protium99.99%99.99%

Deuterium0.01%0.01%

Deuterium0.01%0.01%

TritiumTrace %Trace %TritiumTrace %Trace %

Average Atomic weightAverage Atomic weight of Hydrogen = 1.007941.00794 amuamu

2 - 3CH 104

Isotopes of CarbonIsotopes of Carbon

Average Atomic weightAverage Atomic weight of C= 12.01112.011 amuamu

98.89%98.89%

CC661212 CC66

1313CC66

1414

1.11%1.11% Trace %Trace %

++++

++++

++ ++

--

--

--

--

----

--

++++

++++

++ ++

--

---- --

--++

++

++++

++ ++

--

--

--

----

--

2 - 4CH 104

Radioactive IsotopesRadioactive Isotopes

CC661414

++++

++++

++ ++

--

--

--

----

--++

31

H--

Nucleus is unstableSo falls apart (decays)

Giving radioactive particles

Nucleus is unstableSo falls apart (decays)

Giving radioactive particles

Hydrogen-3Hydrogen-3Carbon-14Carbon-14

2 - 5CH 104

Radioactive Isotopes in MedicineRadioactive Isotopes in Medicine

TcTc434399m99m

123123 5353

II

131131 5353

II

60602727

CoCo

Diagnose thyroid functionDiagnose thyroid function

Treat hyperthyroid Treat hyperthyroid (destroys cells)(destroys cells)

Destroy tumors Destroy tumors (( radiation) radiation)

Diagnose bone, tissue Diagnose bone, tissue (most common)(most common)

2 - 6CH 104

Alpha DecayAlpha Decay

PbPb8282206206 ++

++

++++

++ ++

2102108484 Po

44

22HeHe ++ ++

ParticleParticle

2102108484 Po PbPb8282

206206 + 44

22HeHe

2 - 7CH 104

Beta DecayBeta Decay

NN771414

141466 CC

00

-1-1ee --

ParticleParticle++

++

++++

++ ++ ++++

++++

++ ++++

++ - -

11

00nn

11

11HH +

00

-1-1ee

neutron proton electron

2 - 8CH 104

Beta DecayBeta Decay

NN771414

141466 CC

00

-1-1ee --

ParticleParticle++

++

++++

++ ++ ++++

++++

++ ++++

++ - -

+00

-1-1ee1414

66 CC NN771414

2 - 9CH 104

Gamma DecayGamma Decay

99m99m4343 TcTc decaydecay

++++

++++

++ ++ ++++

++++

++ ++

99994343 TcTc

+99m99m4343 TcTc TcTc4343

9999

2 - 10CH 104

Radiation: Penetration through AirRadiation: Penetration through Air

++ ++

--

2 - 4 cm2 - 4 cm

200 - 300 cm200 - 300 cm

500 m500 m

2 - 11CH 104

Radiation: ShieldingRadiation: Shielding

++ ++

--

Paper Paper ClothCloth

Heavy Heavy ClothCloth

Pb, thick Pb, thick concreteconcrete

2 - 12CH 104

++ ++

--

Tissue Penetration DepthTissue Penetration Depth

0.05 mm0.05 mm

4-5 mm4-5 mm

>50 cm>50 cm

2 - 13CH 104

Nuclear EquationsNuclear Equations

2262268888 Ra RnRn8686

222222 + 44

22HeHe

Radon gas in BuildingsRadon gas in Buildings

PoPo8484218218 + 44

22HeHe

2 - 14CH 104

1311315353 I XeXe5454

131131 + 00

-1-1ee

Thyroid check & treatmentThyroid check & treatment

Cancer TreatmentCancer TreatmentNuclear EquationsNuclear Equations

60602727 Co NiNi2828

6060 + 00

-1-1ee

2 - 15CH 104

Radiation DetectionRadiation Detection

1 Ci = 3.7 x 1010disintegrations sec

1 Bq = 1 disintegration sec

# of disintegrations by of 1g Ra

ActivityActivityActivityActivity

Becquerel (Bq)Becquerel (Bq)

Curie (Ci)Curie (Ci):

2 - 16CH 104

Radiation DetectionRadiation Detection

Absorbed DoseAbsorbed DoseAbsorbed DoseAbsorbed Dose

2 - 17CH 104

Radiation DetectionRadiation Detection

++ ++

--

0.05 mm0.05 mm

4-5 mm4-5 mm

>50 cm>50 cm

Tissue Penetration DepthTissue Penetration Depth

Absorbed DoseAbsorbed DoseAbsorbed DoseAbsorbed Dose

2 - 18CH 104

++ ++

--

0.05 mm0.05 mm

4-5 mm4-5 mm

>50 cm>50 cm

Radiation Absorbed Dose (Rad) (D)Radiation Absorbed Dose (Rad) (D): Radiation Absorbed Dose (Rad) (D)Radiation Absorbed Dose (Rad) (D):

1 rad = 1 rad = 1 x 101 x 10-2-2 JJ

1 kg tissue1 kg tissue1 rad = 1 rad = 1 x 101 x 10-2-2 JJ

1 kg tissue1 kg tissue1 rad = 1 rad = 2.4 x 102.4 x 10-3 -3 calcal

1 kg tissue1 kg tissue1 rad = 1 rad = 2.4 x 102.4 x 10-3 -3 calcal

1 kg tissue1 kg tissue

100 rad = 1 Gray (Gy)100 rad = 1 Gray (Gy)100 rad = 1 Gray (Gy)100 rad = 1 Gray (Gy)

2 - 19CH 104

Radiation DetectionRadiation Detection

Biological Damage Biological Damage Biological Damage Biological Damage

2 - 20CH 104

Radiation Equivalent for Man (rem)Radiation Equivalent for Man (rem)

1 rem1 rem = 1 rad x RBERBE

RBERBE2020

11

11

RBERBE2020

11

11

Damage (rem) = absorbed dose (rad) X Damage (rem) = absorbed dose (rad) X factorfactor

(relative biological effectiveness)(relative biological effectiveness)

100 rem100 rem = 1 sievert (Sv)

2 - 21CH 104

Annual Radiation Exposure in USAAnnual Radiation Exposure in USA

Ground = 15 mrem

Air, H2O, Food = 30 mrem

Cosmic = 40 mremCosmic = 40 mrem

Wood,concrete,bricks = 50 mremWood,concrete,bricks = 50 mrem

X-rays: Chest = 50 mremDental = 20

Smoking = 35 mrem

TV = 2 mrem

Radon = 200 mrem

2 - 22CH 104

Biological Effects of RadiationBiological Effects of Radiation

Dose in remDose in rem0-250-25 genetic damage possible but genetic damage possible but usually undetectedusually undetected

25-10025-100 decrease # of white blood decrease # of white blood cells (temporary)cells (temporary)

100-200100-200 mild radiation sickness mild radiation sickness (vomit, diarrhea, strong decrease # (vomit, diarrhea, strong decrease # white blood cells)white blood cells)

>300>300 (diarrhea, hair loss, infection) (diarrhea, hair loss, infection)

500500 LDLD50 50 for humansfor humans

Dose in remDose in rem0-250-25 genetic damage possible but genetic damage possible but usually undetectedusually undetected

25-10025-100 decrease # of white blood decrease # of white blood cells (temporary)cells (temporary)

100-200100-200 mild radiation sickness mild radiation sickness (vomit, diarrhea, strong decrease # (vomit, diarrhea, strong decrease # white blood cells)white blood cells)

>300>300 (diarrhea, hair loss, infection) (diarrhea, hair loss, infection)

500500 LDLD50 50 for humansfor humans

2 - 23CH 104

300 300 LDLD50 50 for dogsfor dogs

500500 LDLD50 50 for humansfor humans

800 800 LDLD50 50 for ratsfor rats

50,000 LD50,000 LD50 50 for Bacteriumfor Bacterium

100,000 LD100,000 LD50 50 for Insectsfor Insects

Biological Effects of RadiationBiological Effects of RadiationDose in remDose in rem

2 - 24CH 104

Half-LifeHalf-Life

tt1/21/2 = Time for 1/2 sample to decay = Time for 1/2 sample to decay

m = g(0.5)tm = g(0.5)t

1311315353 I

20 g

tt1/21/2 = =

8 days8 days10 g

8 days8 days

5 g

Mass remaining

Beginning mass

# of half lifes

2 - 25CH 104

2 - 26CH 104

m = g(0.5)ttm = g(0.5)tt

1311315353 I

20. g

tt1/21/2 = =

8 days8 days10. g

8 days8 days

5.0 g

How much I-131 will be left after 72 days?How much I-131 will be left after 72 days?

Half-LifeHalf-Life

= 20. g(0.5)9= 20. g(0.5)9

72 days 1

1 half-life = 8 days

99 half-lifes

= .039 g= .039 g

2 - 27CH 104

Positron Emission TomographyPositron Emission Tomography

PETPET

2 - 28CH 104

FissionFission

23592 U

10

n 23692 U

+

9136Kr

14256Ba

unstable

Splitting atoms for Energy

2 - 29CH 104

FissionFission

Need critical mass of U-235

2 - 30CH 104

42

He

FusionFusion

21 H

31

H++

++

DeuteriumDeuterium

TritiumTritium

++ ++ + +

10

n

Combining atoms for Energy

2 - 31CH 104

FusionFusion

2 - 32CH 104

2 - 33CH 104