radioactive elements. radioactivity: an imbalance of forces in the nucleus

Download Radioactive Elements. Radioactivity: An Imbalance of Forces in the Nucleus

Post on 03-Jan-2016

214 views

Category:

Documents

1 download

Embed Size (px)

TRANSCRIPT

  • RadioactiveElements

  • Radioactivity: An Imbalance of Forces in the Nucleus

  • Radioactivity: An Imbalance of Forces in the NucleusStrength of Force depends on distance !

  • Radioactivity: An Imbalance of Forces in the NucleusStrength of force depends on distance SO.. Larger nuclei are less stableStrong force less effective in holding nucleus togetherElectrical (repulsive) forces have greater impact Elements DECAY (come apart) over time

  • Radioactivity: DefinitionRadioactivity: the process by which certain elements emit particular forms of radiation. Radioactive: any element that emits any of these forms of radiation.

  • Half Life: Measures Decay RateHalf life refers to amount of time it takes for of the radio active sample to decay Half life for a particular isotope is always the same

  • Half LifeHalf life measures decay rateEx. Every1620 years of a sample of radium-226 will have decayed. Start1620 years3240 years6480 years

  • Application: Carbon Dating

  • Reaction in a Nuclear Reactor

  • RadioactiveElementsPart 2Jan 9, 2014

  • Different Ways to Decay Types of Radioactive ParticlesAlpha Particles () 2 protons and 2 neutrons

    Beta Particles () split 1 neutron into 1 proton and 1 electron

    Gamma Particles () emits a photon

  • Half-life: Exponential Decay

  • Decay of 238U: Natural Decay Chain

  • Decay of 238U: Natural Decay Chaindecays, through alpha-emission, with a half-life of 4.5 billion years to thorium-234which decays, through beta-emission, with a half-life of 24 days to protactinium-234which decays, through beta-emission, with a half-life of 1.2 minutes to uranium-234which decays, through alpha-emission, with a half-life of 240 thousand years to thorium-230which decays, through alpha-emission, with a half-life of 77 thousand years to radium-226which decays, through alpha-emission, with a half-life of 1.6 thousand years to radon-222which decays, through alpha-emission, with a half-life of 3.8 days to polonium-218which decays, through alpha-emission, with a half-life of 3.1 minutes to lead-214which decays, through beta-emission, with a half-life of 27 minutes to bismuth-214which decays, through beta-emission, with a half-life of 20 minutes to polonium-214which decays, through alpha-emission, with a half-life of 160 microseconds to lead-210which decays, through beta-emission, with a half-life of 22 years to bismuth-210which decays, through beta-emission, with a half-life of 5 days to polonium-210which decays, through alpha-emission, with a half-life of 140 days to lead-206, which is a stable nuclide.

  • Types of Radioactive ParticlesAlpha Particles 2 protons and 2 neutrons

    Beta Particles split 1 neutron into 1 proton and 1 electron

    Gamma Particles emits a photon

  • Types of Radioactive ParticlesAlpha Particles 2 protons and 2 neutronsLowest EnergyStill fast enough to do damageEasily stoppedRelatively large size and massLarge enough to do damageEasily stopped+2 Charge. Tends to pick up electrons & convert to Helium

  • Types of Radioactive ParticlesAlpha Particles Emits: 2 p + 2 n Example: Uranium-238 Thorium-234 + Helium-4

    ElementAtomic #(# protons)Mass # (# p + # n)# neutronsUranium92238146Thorium90234144Helium242

  • Types of Radioactive ParticlesBeta Particles - 1 n 1 p + 1 e- (emits e-)Higher EnergyHarder to stop than particleBecomes part of material when stopped-1 Charge. Proton joins nucleusElectron (-1 charge) is emitted

  • Types of Radioactive ParticlesBeta Particles Loses: 1 n Gains: 1 p Emits: 1 e- Example: Thorium -234 Protactinium 234 + electron

    ElementAtomic #(# protons)Mass # (# p + # n)# neutronsThornium90234144Protactinium91234143

  • Types of Radioactive ParticlesGamma Particles emits a photonHighest EnergyCan do significant damageHard to stopNo chargeDoesnt combine with other materialsNo massHard to stop

  • Types of Radiation: Energy (Resistance to being stopped)

  • Types of Radiation: Charges

  • Types of Radiation: Charges

Recommended

View more >