1 / 38

Chapter 20

Chapter 20. Nuclear Chemistry. Nuclear Terminology. nuclide - type of atom specified by its atomic number, atomic mass, and energy state, such as carbon 14 nucleon - proton or a neutron, especially as part of an atomic nucleus

cedric-hicks
Download Presentation

Chapter 20

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 20 Nuclear Chemistry

  2. Nuclear Terminology nuclide - type of atom specified by its atomic number, atomic mass, and energy state, such as carbon 14 nucleon - proton or a neutron, especially as part of an atomic nucleus unstable isotope - a natural or artificially created isotope having an unstable nucleus that decays, emitting alpha, beta, or gamma rays until stability is reached

  3. Types of Radioactivity

  4. Types of Radioactivity alpha => a42He 21284Po => 20882Pb + 42He

  5. Types of Radioactivity beta => b => 0-1b 10n => 11p + 0-1b 9843Tc => 9844Ru + 0-1b

  6. Types of Radioactivity gamma => g => 00g 23090Th* => 23090Th + 00g

  7. Uranium Series4n + 2 Decay Series

  8. beta decay for nuclides above zone of stability positron decay for nuclides below zone of stability Predicting Decay Modes

  9. Band of Stability

  10. Nuclear Stability • the number of neutrons is equal to or greater than the number of protons in a stable nucleus (exceptions H-1 and He-3) • the number of protons and neutrons is nearly equal for low atomic number elements • usually the isotopes within the band of stability are stable

  11. Nuclear Stability • above Z=20, the number of neutrons exceeds the number of protons in stable nuclides • usually nuclides with even numbers of protons, neutrons or both are stable • certain magic numbers confer unusually stable nuclides(2, 8, 20, 26, 28, 50, 82, & 126) • above Z= 83 the elements have no stable isotopes

  12. Binding Energy • difference between the mass of a nuclide and the sum of the masses of the nucleons in the nucleus Dm = mass of nuclide - sum of mass of nucleons E = Dmc2

  13. Binding Energy per Nucleon

  14. Half Life • time required for 1/2 of the radioactive nuclide to decay, t1/2

  15. Rates of Radioactive Decay Relationships of concentrations and rate ln([A]t) = - kt + ln([A]o) ln([A]o/[A]t) = kt Half-life of radioactive decay t1/2 = 0.693/k

  16. Selected Half Lives

  17. Decay of Plutonium-239

  18. Detection of Radioactivity • film badge • scintillation counter • Geiger counter => ionizes gas

  19. Relationships of Concentrations ln(#radioactive atomst/#radioactive atomso) = - kt

  20. Dating Artifacts by Radioactivity Carbon-14 Dating • t1/2 = 5730 yr • while alive, plants constantly replace C-14 • after death the C-14 will decay at a known rate

  21. Glenn Seaborg • proposed that transuranium elements were another series like the rare earths • 1940-1961, he and colleagues, created 10 new elements • 1951 Noble Prize for creating new elements • Z=106, Sg, Seaborgium

  22. Nuclear Transmutation 24296Cm + 42He => 24598Cf + 10n 6428Ni + 20983Bi => 272111Uuu + 10n 8656Kr + 20882Pb => 293118Uuo + 10n

  23. Fission Reactions • nuclear reaction in which an atomic nucleus, splits into two nearly equal mass fragments with the evolution of a tremendous amount of energy

  24. Nuclear Fission

  25. Nuclear Fission

  26. Nuclear Power Plant

  27. Share of Electricity Generatedby Nuclear Energy

  28. Notable Nuclear Accident Mar. 28, 1979—One of the reactors at Three Mile Island in Middletown, PA suffered the worst commercial nuclear accident in the U.S. as a loss of coolant led to a partial core meltdown.

  29. Reactor Terminology critical mass • The smallest mass of a fissionable material that will sustain a nuclear chain reaction at a constant level. breeder reactor • A nuclear reactor that produces as well as consumes fissionable material, especially one that produces more fissionable material than it consumes.

  30. Nuclear Fusion • nuclear reaction where smaller particles are joined together to form larger particles 4 11H =>42He + 2 0-1e 21H + 21H => + 10n 11H + 32He =>42He + 0-1e

  31. Radiation Units roentgen - dosage of x-rays and g-rays - deposition of 93.3  10-7 J per gram of tissue rad (radiation absorbed dose) - dose of 1.00  10-2 J absorbed per kilogram of material gray - SI unit equal to the absorption of 1 J per kilogram of material

  32. Background Radiation

  33. Radiation Sickness Illness induced by ionizing radiation, ranging in severity from nausea, vomiting, headache, and diarrhea to loss of hair and teeth, reduction in red and white blood cell counts, extensive hemorrhaging, sterility, and death.

  34. Radon • radioactive, noble gas produced by decomposition of naturally occurring uranium deposits in the soil • decays by alpha emission producing other alpha emitters • common household hazard where the home is built on a conventional foundation over soil containing trace amounts of uranium

  35. Radon • Inhalation hazard 22286Rn =>42He + 21884Po 21884Po =>42He + 21482Pb

  36. Use of Isotopes as Tracers • radioactive isotope is introduced into a biological system to follow the course of a process • provides information on the process

  37. Tracers

  38. Diagnostic Radioisotopes

More Related