TOPIC: Benefits & Dangers of: TOPIC: Benefits & Dangers of: RadioisotopesRadioisotopes

Do Now: Do Now: Draw Bohrs Model for the Draw Bohrs Model for the Cl-35 isotopeCl-35 isotope

RADIOISOTOPERADIOISOTOPE- isotopes who’s nucleus is - isotopes who’s nucleus is

unstable and dissipate excess unstable and dissipate excess energy by spontaneously energy by spontaneously

emitting radioactive particles emitting radioactive particles (we will learn about these next (we will learn about these next

week) week)

Carbon-14Carbon-14

Carbon DatingCarbon Dating

Not that kind of dating?

!

C-14 used to date organic (previously living) materials

U-238 decay seriesU-238 decay seriesU-238 decays to Pb-206 (many steps)U-238 decays to Pb-206 (many steps)

Over time, amount of U Over time, amount of U and amount of and amount of Pb Pb –Scientists use the ratio of U-238 Scientists use the ratio of U-238

to Pb-206 to to Pb-206 to date rocksdate rocks

Radioactive TracersRadioactive Tracers

Determine the way in which a chemical Determine the way in which a chemical reaction occurreaction occur– P-31: determines P uptake in plantsP-31: determines P uptake in plants– C-14: maps C in metabolic processesC-14: maps C in metabolic processes– C-14: maps organic molecules and figures out C-14: maps organic molecules and figures out

reaction mechanismsreaction mechanisms

Used to track the distribution of a Used to track the distribution of a substance in cells/tissues in the bodysubstance in cells/tissues in the body

MedicalMedical

radioisotopes with radioisotopes with shortshort half-lives (quickly half-lives (quickly eliminated from the body)eliminated from the body)– Tracers in medical diagnosisTracers in medical diagnosis– Treatment of cancerTreatment of cancer

I-131: Diagnosis & treat thyroid disordersI-131: Diagnosis & treat thyroid disordersCo-60: gamma emitter Co-60: gamma emitter – Used to kill cancerous tumorsUsed to kill cancerous tumors

Tc-99: treatment of brain cancerTc-99: treatment of brain cancer

Industrial ApplicationsIndustrial Applications

Kill bacteria and spores in food and mailKill bacteria and spores in food and mailCo-60: kills bacteria in foodsCo-60: kills bacteria in foods

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Power PlantsPower PlantsUsed as a fuel source to generate electricityUsed as a fuel source to generate electricityNo contributions to greenhouse gasesNo contributions to greenhouse gases

Radiation RisksRadiation Risks

Can Can damage normal tissuedamage normal tissueHigh doses can cause High doses can cause illness & deathillness & deathCan cause Can cause mutations in DNAmutations in DNADisposal of waste is difficult (esp. from Disposal of waste is difficult (esp. from nuclear power plants)nuclear power plants)

Have long half-lives and remain radioactive Have long half-lives and remain radioactive for long periods of timefor long periods of time

Chernobyl