Nuclear Chemistry PPT PDF

Nuclear Chemistry What is a nuclear reaction?  Nuclear Chemistry  Nuclear reactions involve the nucleus  Protons and neutrons  Involve massive amounts of energy  Radioactivity is the process by which particles or rays are emitted from an atom  Radioacti...

Nuclear Chemistry What is a nuclear reaction?  Nuclear Chemistry  Nuclear reactions involve the nucleus  Protons and neutrons  Involve massive amounts of energy  Radioactivity is the process by which particles or rays are emitted from an atom  Radioactive Decay  Unstable nuclei break down into smaller, more stable atoms.  Often forms new element  Half life  Fission reaction  Atoms are ‘split’  Unequal parts  Natural process  Types of Radiation  Alpha radiation  Alpha particle= α = 4He2+ = helium nucleus  226Ra  α + ?  222Rn; new element and new mass number To balance equation balance protons and neutrons in reactants and products  Alpha particles are a low energy form of radiation May be stopped with a piece of paper Only medically dangerous if inhaled or ingested  Types of Radiation  Beta Radiation  Beta particle= β = e- = -10e  Fastmoving, high energy electrons that are emitted from the nucleus  nβ+p 14C  14N + β  Mass number remains unchanged, but new element  Can be stopped with thin sheets of metal  Can penetrate skin and cause mutations in DNA  Types of Radiation  Gamma Radiation  Gamma ray (energy, not a particle)= γ  Often emitted with alpha and beta particles  Source of most energy during radioactive decay  238U 234Th + α + 2γ  Varying degrees of energy, but usually requires feet of concrete or lead to be stopped  Highly mutagenic  Nuclear Reactors  Induce fission by firing slow moving neutrons at 235 U nuclei.  Split produces two daughter atoms, free neutrons, and gamma rays  Energy from gamma rays is harnessed to create steam  Free neutrons induce other atoms to split  Pb rods absorb some neutrons to control rate of reaction  Fusion  Taking light atoms and forcing them to combine into heavier elements  H-bomb  Sun  Requires a massive amount of energy to get started  Yields tremendous amount of energy  Difficult to control beyond amount of fuel