1 Ch 9 - Nuclear Radiation 1.Nuclear Emissions 2.Nuclear Equations 3.Producing Radioactive Isotopes 4.Half-Life 5.Nuclear Fission and Fusion 6.Uses & Effects.

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  • Ch 9 - Nuclear RadiationNuclear EmissionsNuclear EquationsProducing Radioactive IsotopesHalf-LifeNuclear Fission and FusionUses & Effects

  • ReviewRememberProtons: + chargeNeutrons: neutral Electrons: - charge atomic symbolatomic number number of protonsmass number number of protons and neutronsNuclear Symbols notice mass number is on top

  • 1. Nuclear EmissionsRadiation comes from the nucleus of an atom.Unstable nucleus emits a particle or energy alpha beta

    gamma

    non-radioactive particle = neutron

  • Alpha Particle

    Same as a helium nucleus(He) 4 2 He or

    Two protonsTwo neutrons

  • Beta Particle An electron emitted from the nucleus 0e or 1A neutron in the nucleus breaks down11 0 n H +e 0 1 -1

  • Gamma Radiation Pure radiation

    Like an X-ray but comes from the nucleus

  • Radiation Protection Shieldingalpha paper, clothingbeta lab coat, glovesgamma- lead, thick concreteLimit time exposedKeep distance from source

  • Radiation Protection

  • 2. Nuclear Equations In the reactants and products

    Atomic numbers must balanceandMass numbers must balance

  • Alpha decay

  • Beta decay

    234Th 234Pa + 0e 90 91 1beta particle

  • Gamma radiationNo change in atomic or mass number

    11B 11B + 0 5 5 0 boron atom in a high-energy state

  • Learning CheckTo predict the product, simply remember that the mass number and atomic number are conserved

    What is the identity of X?

  • Learning CheckWrite the nuclear equation for the beta emitter Co-60.

  • Solutions

    60Co 60Ni + 0 e 27 28 -1 93239Np

  • 3. Producing Radioactive IsotopesBombardment of atoms produces radioisotopes = 60 = 6059Co + 1n 56Mn + 4H e 27 0 25 2 = 27= 27 cobalt neutron manganese alpha atom radioisotope particle

  • Learning CheckWhat radioactive isotope is produced in the following bombardment of boron?10B + 4He ? + 1n 5 2 0

  • SolutionWhat radioactive isotope is produced in the following bombardment of boron?10B + 4He 13N + 1n 5 2 7 0 nitrogen radioisotope

  • 4. Half-Life of a RadioisotopeThe time for the radiation level to fall (decay) to one-half its initial value

  • Examples of Half-LifeIsotope Half lifeC-152.4 secRa-2243.6 daysRa-22312 daysI-12560 daysC-145700 yearsU-235710 000 000 years

  • Learning Check The half life of I-123 is 13 hr. How much of a 64 mg sample of I-123 is left after 26 hours?

  • Solutiont1/2 =13 hrs 26 hours = 2 x t1/2Amount initial =64mg Amount remaining = 64 mg x x = 16 mg

  • 5. Fission VS FusionFissionlarge nuclei break up235U + 1n 139Ba + 94Kr + 3 1n + 92 0 56 36 0

    Energy

  • Fission of Uranium-235Chain reaction the reaction sustains itself by producing more neutrons

  • Nuclear FusionFusion small nuclei combine

    2H + 3H 4He + 1n + 1 1 2 0

    Occurs in the sun and other starsEnergyExcessive heat can not be containedAttempts at cold fusion have FAILED.Hot fusion is difficult to contain

  • Learning CheckIndicate if each of the following areFission(2) fusion

    Nucleus splits Large amounts of energy releasedSmall nuclei form larger nucleiHydrogen nuclei react

    Energy

  • SolutionIndicate if each of the following areFission(2) fusion

    1 Nucleus splits 1 + 2 Large amounts of energy released 2 Small nuclei form larger nuclei 2 Hydrogen nuclei react

  • 6. Uses & EffectsRadiation - treatment of cancerNuclear medicine - use of radioisotopes in diagnosisTracers small amounts of radioactive substances used as probes to study internal organsNuclear imaging medical techniques involving tracersFood IrradiationFood - irradiated with g rays from 60Co or 137Cs.Irradiated milk - shelf life of 3 mo. w/o cooling.USDA - approved irradiation of meats and eggs

  • Exposure Sources

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