Nuclear ChemistrySlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Nuclear ChemistryChapter 23Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.XAZMass Number Atomic NumberElement SymbolAtomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutronsAZ1p11H1orproton1n0neutron0e-10-1orelectron0e+10+1orpositron4He242or particle11100-10+14223.1Balancing Nuclear Equations1. Conserve mass number (A). The sum of protons plus neutrons in the products must equal the sum of protons plus neutrons in the reactants.1n0U23592+Cs13855Rb96371n0+ + 2235 + 1 = 138 + 96 + 2x12. Conserve atomic number (Z) or nuclear charge. The sum of nuclear charges in the products must equal the sum of nuclear charges in the reactants.1n0U23592+Cs13855Rb96371n0+ + 292 + 0 = 55 + 37 + 2x023.1212Po decays by alpha emission. Write the balanced nuclear equation for the decay of 212Po.4He242oralpha particle - 212Po 4He + AX842 Z212 = 4 + A A = 20884 = 2 + Z Z = 82212Po 4He + 208Pb842 8223.123.1Nuclear Stability and Radioactive DecayBeta decay14C 14N + 0 + 67-140K 40Ca + 0 + 1920-11n 1p + 0 + 01-1Decrease # of neutrons by 1Increase # of protons by 1Positron decay11C 11B + 0 + 65+138K 38Ar + 0 + 1918+11p 1n + 0 + 10+1Increase # of neutrons by 1Decrease # of protons by 1 and  have A = 0 and Z = 023.2Electron capture decayIncrease # of neutrons by 1Decrease # of protons by 1Nuclear Stability and Radioactive Decay37Ar + 0e 37Cl + 1817-155Fe + 0e 55Mn + 2625-11p + 0e 1n + 10-1Alpha decayDecrease # of neutrons by 2Decrease # of protons by 2212Po 4He + 208Pb842 82Spontaneous fission252Cf 2125In + 21n9849 023.2n/p too largebeta decayXn/p too smallpositron decay or electron captureY23.2Nuclear Stability•Certain numbers of neutrons and protons are extra stable•n or p = 2, 8, 20, 50, 82 and 126•Like extra stable numbers of electrons in noble gases (e- = 2, 10, 18, 36, 54 and 86)•Nuclei with even numbers of both protons and neutrons are more stable than those with odd numbers of neutron and protons•All isotopes of the elements with atomic numbers higher than 83 are radioactive•All isotopes of Tc and Pm are radioactive23.2Nuclear binding energy (BE) is the energy required to break up a nucleus into its component protons and neutrons.BE + 19F 91p + 101n910BE = 9 x (p mass) + 10 x (n mass) – 19F massE = mc2BE (amu) = 9 x 1.007825 + 10 x 1.008665 – 18.9984BE = 0.1587 amu1 amu = 1.49 x 10-10 JBE = 2.37 x 10-11Jbinding energy per nucleon = binding energynumber of nucleons= 2.37 x 10-11 J19 nucleons= 1.25 x 10-12 J23.2Nuclear binding energy per nucleon vs Mass numbernuclear stability23.2nuclear binding energynucleonKinetics of Radioactive DecayN daughterrate = -Ntrate = NNt= N-N = N0exp(-t) lnN = lnN0 -  tN = the number of atoms at time tN0 = the number of atoms at time t = 0 is the decay constantln2=t½23.3Kinetics of Radioactive Decay[N] = [N]0exp(-t)ln[N] = ln[N]0 -  t[N]ln [N]23.3Radiocarbon Dating14N + 1n 14C + 1H7 16014C 14N + 0 + 67-1t½ = 5730 yearsUranium-238 Dating238U 206Pb + 8 4 + 6 092 -182 2t½ = 4.51 x 109 years23.3Nuclear TransmutationCyclotron Particle Accelerator14N + 4 17O + 1p728127Al + 4 30P + 1n13215014N + 1p 11C + 4716223.4Nuclear Transmutation23.4Nuclear Fission23.5235U + 1n 90Sr + 143Xe + 31n + Energy9254380 0Energy = [mass 235U + mass n – (mass 90Sr + mass 143Xe + 3 x mass n )] x c2Energy = 3.3 x 10-11J per 235U= 2.0 x 1013 J per mole 235UCombustion of 1 ton of coal = 5 x 107 JNuclear Fission23.5235U + 1n 90Sr + 143Xe + 31n + Energy9254380 0Representative fission reactionNuclear Fission23.5Nuclear chain reaction is a self-sustaining sequence of nuclear fission reactions.The minimum mass of fissionable material required to generate a self-sustaining nuclear chain reaction is the critical mass.Non-criticalCriticalSchematic Diagram of a Nuclear Reactor23.5Annual Waste Production23.535,000 tons SO24.5 x 106 tons CO21,000 MW coal-firedpower plant3.5 x 106 ft3 ash1,000 MW nuclearpower plant70 ft3 vitrified wasteNuclear Fission23.5Nuclear FissionHazards of the radioactivities in spent fuel compared to uranium oreFrom “Science, Society and America’s Nuclear Waste,” DOE/RW-0361 TGChemistry In Action: Nature’s Own Fission ReactorNatural Uranium0.7202 % U-235 99.2798% U-238Measured at Oklo0.7171 % U-23523.6Nuclear Fusion2H + 2H 3H + 1H1111Fusion Reaction Energy Released2H + 3H 4He + 1n11206Li + 2H 2 4He3126.3 x 10-13 J2.8 x 10-12 J3.6 x 10-12 JTokamak magnetic plasma confinement23.7Radioisotopes in Medicine•1 out of every 3 hospital patients will undergo a nuclear medicine procedure•24Na, t½ = 14.8 hr,  emitter, blood-flow tracer•131I, t½ = 14.8 hr,  emitter, thyroid gland activity•123I, t½ = 13.3 hr, ray emitter, brain imaging•18F, t½ = 1.8 hr,  emitter, positron emission tomography•99mTc, t½ = 6 hr, ray emitter, imaging agentBrain images with 123I-labeled compound23.7Radioisotopes in Medicine98Mo + 1n 99Mo42042235U + 1n 99Mo + other fission products92 0 4299mTc 99Tc + -ray434399Mo 99mTc + 0 + 4243 -1Research production of 99MoCommercial production of 99Mot½ = 66 hourst½ = 6 hoursBone Scan with 99mTcGeiger-Müller Counter23.723.8Biological Effects of RadiationRadiation absorbed dose (rad)1 rad = 1 x 10-5 J/g of materialRoentgen equivalent for man (rem)1 rem = 1 rad x Q Quality Factor-ray = 1 = 1 = 20Chemistry In Action: Food IrradiationDosage EffectUp to 100 kiloradInhibits sprouting of potatoes, onions, garlics. Inactivates trichinae in pork. Kills or prevents insects from reproducing in grains, fruits, and vegetables.100 – 1000 kilorads Delays spoilage of meat poultry and fish. Reduces salmonella. Extends shelf life of some fruit.1000 to 10,000 kiloradsSterilizes meat, poultry and fish. Kills insects and microorganisms in spices and