2 - 1 CH 104 Chapter 13: Nuclear Chemistry Radioactivity Nuclear Equations Radiation Detection Half-Life Medical Applications Radiometric Dating Fission & Fusion

2 - 2 CH 104

2 - 3 CH 104 Isotopes of Hydrogen Isotopes = Isotopes = Atoms of the same element but having different masses H H H Protium99.99% Deuterium0.01% Tritium Trace % Average Atomic weight Average Atomic weight of Hydrogen amu = amu

2 - 4 CH 104 Isotopes of Carbon Average Atomic weight amu Average Atomic weight of C= amu 98.89% C 612C 613 C % Trace %

2 - 5 CH 104 Radioactive Isotopes C H - Nucleus is unstable So falls apart (decays) Giving radioactive particles Hydrogen-3 Carbon-14

2 - 6 CH 104 Radioactive Isotopes in Medicine Tc 4399m I 131 I 6027 Co Diagnose thyroid function Treat hyperthyroid (destroys cells) Destroy tumors (  radiation) Diagnose bone, tissue (most common)

2 - 7 CH 104 Alpha Decay Pb Po 42 He ++  Particle Po Pb He Transmutation: Transmutation: one element changes to another

2 - 8 CH 104 Beta Decay N C 0 e -  Particle n 11 H + 0 e neutronprotonelectron

2 - 9 CH 104 Beta Decay N C 0 e -  Particle e 146 C N 7 14

CH 104 Gamma Decay 99m43 Tc  decay Tc + 99m43 Tc Tc 

CH 104 Ionizing Radiation - Radiation knocks off an electron An ion A radical Ions & radicals cause damaging chain reactions

CH 104 Geiger Counter - Radiation knocks off an electron An ion Ions detected by Counter Gas in instrument tube

CH 104 Radiation: Penetration through Air ++ -  cm cm 500 m

CH 104 Radiation: Shielding ++ -  Paper Cloth Heavy Cloth Pb, thick concrete

CH -  Tissue Penetration Depth 0.05 mm 4-5 mm 4-5 mm >50 cm

CH 104 Nuclear Equations Ra Rn He  Radium    Radon gas in Buildings Po He

CH I Xe e  Thyroid check & treatment  Cancer Treatment Nuclear Equations 6027 Co Ni e

CH 104 Radiation Detection 1 Ci = 3.7 x disintegrations sec 1 Bq = 1 disintegration sec # of disintegrations by of 1g Ra ActivityActivity Becquerel (Bq) Curie (Ci) Curie (Ci):

CH 104 Radiation Detection Absorbed Dose

CH  -   Tissue Penetration Depth 0.05 mm mm >50 cm Radiation Absorbed Dose (Rad) (D) Radiation Absorbed Dose (Rad) (D): 1 rad = 0.01 J kg tissue kg tissue 1 rad = 0.01 J kg tissue kg tissue 1 rad = cal kg tissue kg tissue Radiation Detection: Biological Effect 100 rad = 1 Gray

CH 104 Radiation Detection Biological Damage

CH 104 Roentgen Equivalent for Man (rem)    1 remW R 1 rem = 1 rad x W R W R 2011 WRWRWRWR2011 Damage (rem) = absorbed dose (rad) X factor Quality Factor (Q) = Radiation Weighting factor W R Radiation Weighting factor W R 100 rem 100 rem = 1 sievert (Sv)

CH 104 Learning Check

CH 104 Learning Check: Solution

CH 104 Annual Radiation Exposure in USA Ground = mrem Air, H 2 O, Food = 30 mrem Cosmic = mrem Wood,concrete,bricks = 50 mrem X-rays: Chest = 50 mrem Dental = 20 Smoking Smoking = 35 mrem TV/computers = 12 mrem Radon = 200 mrem Total = mrem / yr

CH 104 Annual Radiation Exposure in USA

CH 104 Biological Effects of Radiation Dose in rem (at one time) 0-25genetic damage possible but usually undetected decrease # of white blood cells (temporary) mild radiation sickness (vomit, diarrhea, strong decrease # white blood cells) >300 (diarrhea, hair loss, infection) 500LD 50 for humans Dose in rem (at one time) 0-25genetic damage possible but usually undetected decrease # of white blood cells (temporary) mild radiation sickness (vomit, diarrhea, strong decrease # white blood cells) >300 (diarrhea, hair loss, infection) 500LD 50 for humans

CH LD 50 for dogs 800 LD 50 for rats 50,000 LD 50 for Bacterium 100,000 LD 50 for Insects Biological Effects of Radiation Dose in rem 500LD 50 for humans

CH 104 4,500 Lymphoma 5,000 – 6,000 Skin cancer 6,000 Lung cancer 6,000 – 7000 Brain Tumor Therapeutic Doses of Radiation Dose in rem

CH 104 FDA approved killing of bacteria with: 0.3 – 1 kGy ionizing radiation from Co-60 or Cs-137 (gamma producers)

CH 104 Half-Life t 1/2 = Time for 1/2 sample to decay I 20 g t 1/2 = 8 days 10 g 8 days 5 g

CH 104 Half-Life I-1318 days Co yrs Tc-99m6 hrs Ra yrs I-1318 days Co yrs Tc-99m6 hrs Ra yrs

CH 104 Half-Life t 1/2 = Time for 1/2 sample to decay I 20 g t 1/2 = 8 days 10 g 8 days 5 g Youtube: Bill Nye Explains Half Life (1:04)

CH I 20. g t 1/2 = 8 days 10. g 8 days 5.0 g How much I-131 will be left after 72 days? Half-Life 72 days 1 1 half-life = 8 days 9 9 half-lifes 20  10  5  2.5  1.25 .625 .3125 .156g

CH 104 Learning Check: Chromium-55 undergoes beta decay wth a half life of 3.5 minutes. What is the primary identity of the sample after decay? 5524 Cr +

CH 104 Learning Check: Solution Chromium-55 undergoes beta decay wth a half life of 3.5 minutes. What is the primary identity of the sample after decay? 5524 Cr Mn e

CH 104 Learning Check: Chromium-55 undergoes beta decay wth a half life of 3.5 minutes. What is the primary identity of the sample after decay? If you start with 120 g; How much Cr-55 will be left after 14 minutes? 5524 Cr Mn e

CH 104 Learning Check: Solution Chromium-55 undergoes beta decay wth a half life of 3.5 minutes Cr 120 g t 1/2 = 3.5 min 60 g 3.5 min What is the primary identity of the sample after decay? If you start with 120 g; How much Cr-55 will be left after 14 minutes? 5524 Cr Mn e (7 min Total) 3.5 min (10.5 min Tot) 3.5 min (14 min Total) 30 g 15 g7.5 g

CH U Th He Th Pa e Natural Decay Series of Uranium-238 What is the product of alpha decay of U-238? What is the product of beta decay of U-238?

CH 104 Natural Decay Series of Uranium U Th He Th Pa e

CH 104 Natural Decay Series of Uranium-238

CH 104 Learning Check

CH 104 Learning Check: Solution

CH 104 Radiometric Dating C-14 dating of artifacts (bones, wood,….); t ½ = 5760 years + 0 e 146 C N 7 14 Issues: Production of C-14 by sun varies in atmosphere. 14 CO 2(g) amounts vary in atmosphere U-238   Pb-206U-235   Pb-207 Issues: Assumes all Pb was once U K  Ar(t ½ K-40 = x 10 9 years) Ca 4019 K Ar Issues: Ar (g) solubility Starting amount of K-40

CH 104 Artificial Transmutation 1 st by Rutherford (1919) New elements all artificially made in particle accelerators. YouTube: How does an atom smashing particle accelerator work? (3:26) Lego particle accelerator:

CH 104 Fission U 1010 n U Kr Ba unstable Splitting atoms for Energy Uses: Atomic BombAtomic Bomb Nuclear PowerNuclear PowerUses: Atomic BombAtomic Bomb Nuclear PowerNuclear Power

CH U Fission

CH U Fission

CH U Fission

CH U Fission

CH U Fission

CH Kr Ba Fission

CH 104 New elements all artificially made in particle accelerators. YouTube: How does an atom smashing particle accelerator work? (3:26) Lego particle accelerator:

CH 104 Fission critical mass Need critical mass of U-235 to sustain chain rxn to produce enough E for an explosion

CH 104 U-235Fission Nuclear Power plants: Controlled fission avoids critical mass Nuclear Power plants: Controlled fission avoids critical mass

CH 104 Uses: SunSun Hydrogen BombHydrogen BombUses: SunSun Hydrogen BombHydrogen Bomb Deuterium Tritium 4242 He Fusion 2121 H 3131 H n Combining atoms for Energy 100,000,000 O C > E than from fission But impractical since heat too high > E than from fission But impractical since heat too high

CH 104 Fusion Making radioactive particles Add 2 stable nuclei  unstable nucleus

CH 104 Learning Check

CH 104 Learning Check: Solution

CH 104 Videos Video: Frontline NOVA Fukushima: Nuclear Aftershocks (53.41 min)

CH 104 B C0+1e + 10 n 11 H e protonneutronpositron Positron Emission Tomography (PET)   Positron

CH 104  rays  image Shows blood flow  rays  image Shows blood flow B C0+1e + Positron Emission Tomography (PET)   Positron B 116 C e positron0e electron  rays Detectable-

CH 104  rays  image Shows blood flow  rays  image Shows blood flow B C0+1e + Positron Emission Tomography (PET)   Positron e electron  rays Detectable-  e electron gamma positron 0 e