# nuclear chemistry

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NUCLEAR CHEMISTRY. An Energetic Concept. WHO DID WHAT. Wilhelm Roentgen Laboratory generated phosphorescence X-rays. WHO DID WHAT. Henri Becquerel Inherited U salts (pitchblende) Natural phosphorescence Discovered spontaneous phosphorescence. WHO DID WHAT. Marie & Pierre Curie - PowerPoint PPT PresentationTRANSCRIPT

NUCLEAR CHEMISTRYAn Energetic Concept

WHO DID WHATWilhelm RoentgenLaboratory generated phosphorescenceX-rays

WHO DID WHATHenri BecquerelInherited U salts (pitchblende)Natural phosphorescenceDiscovered spontaneousphosphorescence

WHO DID WHATMarie & Pierre CurieStudied Becquerel phosphorescence and named itDiscovered Po, Ra

ISOTOPE REVIEWAmass numberZatomic numberA Z = number of neutrons

SO, WHAT IS RADIATION?Instability due to n:p+RadioisotopesGoal is stability

SO, WHAT IS RADIATION?

TYPES OF RADIATIONRutherfordElectric field effect on radioactivityAlphaBetaGamma

TYPES OF RADIATION

TYPES OF RADIATIONAlpha ()Same as a He-4 nucleusA decreases by 4Z decreases by 2

TYPES OF RADIATIONAlphaNot very penetratingStopped by a sheet of paperVery ionizing

TYPES OF RADIATIONBeta ()Same as an electronA remains the sameZ increases by 1

TYPES OF RADIATIONBetaMore penetrating than Stopped by a thin sheet of metalLess ionizing than

TYPES OF RADIATIONGamma ()Pure energyUsually accompanies and More penetrating than and Somewhat blocked by several inches of Pb or several feet of concreteLess ionizing than and

TYPES OF RADIATIONPositron (+)Same mass as Opposite charge of

TYPES OF RADIATIONElectron captureThe opposite of emissionA remains the sameZ decreases by 1

DECAY SERIESContinued radiation until stableFr-221 undergoes the following decay series: ,,,,,

RATE OF RADIOACTIVE DECAYHalf-Lifet = 0.693/kk = rate law constantFirst-order KineticslnN = kt + lnNoNamount after elapsed timet = elapsed timeNo = amount originally

UNITS OF RADIOACTIVE DECAYcurie (Ci)1 Ci = 3.7 x 1010 disintegrations per second~activity of 1 g of Ra-226becquerel (Bq)SI unit1 Bq = 1 dis/s37 GBq = 1 Ci

UNITS OF RADIATION EXPOSUREsievert (Sv)Dose absorbed by specific tissueReplaced rntgen equivalent to man (rem)1 Svnausea2-5 Svhair loss, hemorrhage3 Svdeath in 50% of people in 30 days>6 Svunlikely survivalTypical background exposure is2.4 mSv/year

RATE OF RADIOACTIVE DECAYThe half-life of F-18 is 2 hours. If you receive a dose of 200 mCi at 8:00 AM, how long will it take for 10 mCi to remain in your body? At what time will you have 10 mCi in you?Solve for the value of kPlug into the linear equation and solve for t

RATE OF RADIOACTIVE DECAY2 h = 0.693/k

k = 0.3465 h-1

ln(10 mCi) = (0.3465 h-1)(t) + ln(200 mCi)

ln(10 mCi) ln(200 mCi) = (0.3465 h-1)(t) 2.996= (0.3465 h-1)(t)8.65 h = tat 4:39 PM, you will have 10 mCi in you

RADIOACTIVE DATINGC-14 is a beta emitter with a half-life of 5730 yearsUsed to determine the age of carbon-based substances