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## Presentation on theme: "[http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_17/FG17_04-02d.JPG]"— Presentation transcript:

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Time it takes half of the atoms in a radioactive sample to decay into other atoms. Click Here for Half-Life Demo [http://wps.prenhall.com/wps/media/objects/602/616516/Media_Assets/Chapter22/Text_Images/FG22_02.JPG]

Half-Life Isotope Activity (Curies) U-235 Am-241 3.24 Cs-137 86.4 I-131 123,500 The length of a half-life is related to how active the elements are. (This is measured in curies)

Half-Life Problem: If 13153I has a half-life of 8.04 days, how long will it take until only 25% of it is left?

Half-Life 2 half-lives = 16.08 days

Half-Life Problem: If a fossil only has 12.5% of 146C remaining, how old is it? 5730 x 3 = years

Half-Life Problem: If you start with 25 grams of 13354Xe, which has a half-life of 5.25 days, how much will be left after days?