Applying Name Date Knowledge Section 7.2 Use with textbook pages 302-309. Radioactive decay 1. Define the following terms. (a) half-life Measure of the rate of radioactive decay (b) decay curve The rate at which radioisotopes decay (c) parent isotope I sotore that undergose radioactive decay (d) daughter isotope recation or result serise of decay 2. Complete the following tables. Half-Life Percent Percent of Half-Life Fraction of Fraction of of parent daughter parent isotope daughter isotope isotope isotope O 0 N 2 3 3 15 4 3. A rock sample contains 120 g of a radioactive isotope. The radioactive isotope has a half-life of 5 years (a) Complete the following table. Su Half-Life Time (a) Mass (9) 0 5 W N - 10 9 15 20 UI A 25 (b) How much of the radioactive isotope if left after 25 years have passed? m - 20 (c) How many half-lives have passed if there is only 15 g of the parent isotope left? (d) How many years have passed if there is only 7.5 g of the parent isotope left