Essay on Ch 17 Notes

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Chapter 17 NUCLEAR CHEMISTRY EMBED ChemDraw.Document.5.0 The new nucleus formed is that of Thorium (Th) with 2 fewer protons. Different forms of radiation may be emitted from an unstable radioactive nucleus. 2. Types of radiation -Beta particles are therefore high-speed electrons emitted from the nuclei and, since these are electrons, beta particles have a negative charge and a small mass (0 amu). Beta particles may travel far (2 - 3 m through air). Heavy clothing or one-inch thick wood can be use for protection. EMBED ChemDraw.Document.5.0 - maintain as much distance as possible from the source -use adequate protection -minimize the time of exposure 4. Radiation measurement and Medical applications The curie (Ci) measures the number of nuclear transformations of a radioactive sample. In nuclear medicine, radioisotopes that are given go to specific sites in the body. By detecting the radiation they emit, an evaluation can be made about the location and extent of a tumor for example, or the level of function of a particular organ. Also higher levels of radiation are used to treat or destroy tumors. 5. Half-life The rate of decay for a radioactive isotope varies considerably from one type of nucleus to another. The half-life of a radioisotope is constant and independent of the sample size. The time it takes for half of any sample to decay is called the half-life. EMBED ChemDraw.Document.5.0 Practice sample Using half-life to calculate the amount of radionuclide that remains undecayed after a certain time. The half-life of cobalt-60 is 5.3 yr. if 2.0 g of Co-60 is allowed to decay for a period of 15.9 yr, how many grams of cobalt-60 remain Answer -You must first determine the number of half-lives that have elapsed 15.9 yr x 1 half-life / 5.3 yr 3.0 half-lives Amount of radionuclide undecayed after n half-lives Original amount of radionuclide X 1_ 2n Amount of radionuclide undecayed after 3…