Chapter 21 Nuclear Chemistry

Download Chapter 21 Nuclear Chemistry

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Chapter 21 Nuclear Chemistry. 21.1 Radioactivity. Review from Ch. 2 Subatomic particles Atoms are neutral: # protons = # electrons Isotopes atoms with same number of protons but different number of neutrons. Nuclear Chemistry deals with only the nucleus. - PowerPoint PPT Presentation

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  • Chapter 21Nuclear Chemistry

  • 21.1 RadioactivityReview from Ch. 2Subatomic particlesAtoms are neutral: # protons = # electronsIsotopes atoms with same number of protons but different number of neutrons

    ParticlePositionChargeMass (kg)electronoutside nucleus19.11 x 10-31nucleonprotoninside nucleus+11.67 x 10-27neutroninside nucleus01.67 x 10-27

  • Nuclear Chemistry deals with only the nucleus.nuclide nucleus with specified number of protons and neutronsradioactivity spontaneous emission of radiationradionuclide radioactive nuclideradioisotopes atoms containing radioactive nucleiradioactive decay spontaneous decomposition to form a different, more stable, nucleus with the production of one or more particlesdecay series multiple decay steps through which radioactive nuclides go to reach a stable state

  • Decay Series

  • Common Particles in Radioactive Decay and Nuclear Reactions

    Decay products:alpha () particle42He or 42Common for heavy radionuclidebeta () particle0-1 or 0-1eHigh-speed electrons; atomic number increases when a decay productgamma (g) ray00gHigh-energy photons; often accompanies other decay like electron capturepositron01 or 01eAtomic number decreases when a decay productDecay reactants:electron capture0-1eAddition of electron(s) with production of g raysfission10nNeutron capture causes chain reactions

  • Fission of 235U initiated by neutron capture

  • Chain Fission Reaction

  • Nuclear Equations sum of both mass and atomic numbers on both sides of equation are equalExamples:6831Ga + 0-1e _____

    21287Fr 20885At + ______

    263106Sg ______ + 42He

  • 21.4 Rates of Radioactive DecayRadioactive decay follows 1st order kinetics.All half-lives are equal.

    N # of radioactive nucleik decay constant

    Individual half-lives vary tremendously214Po 2 x 10-4 s144Nd 5 x 1015 year

  • Half-lives

  • Practice exercise, p. 907

  • Practice problem 21.33

  • Practice problem, 90Sr from 1st atomic explosion

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