Macmillan Learning Iridium-192 is one radioisotope used in brachytherapy, in which a radioactive source is placed inside a patient's body to treat cancer. Brachytherapy allows the use of a higher than normal dose to be placed near the tumor while lowering the risk of damage to healthy tissue. Iridium-192 is often used in the head or breast. Use the radioactive decay curve of iridium-192 to answer the three questions. Sample remaining (%) 100 80- 70- 60- 50 40- time: 30- 20. 30 50 60) 70 80 90 100 110 120 130 140 150 160 170 180 190 Time Idays) If the initial sample is 8.00 g. what mass of the original iridium-192 remains after 55 days? 0 mass remaining: 10 20 30 Estimate the half-life of the radioisotope. half-life: How many days would it take for two-thirds of the sample to decay? days days

Fill in the missing symbol in this nuclear chemical equation. Ç0 + H - 0+ He 16 4 8. 2

Part 1.1. If a radioactive element has a half-life of 2.5 million years, the amount of parent material remaining after 10 million years of decay will be what fraction of the original amount? Part 1.2. The half-life of C14 is 5730 years. How old is an artifact that contains 12% of its original C14?

44. Cobalt-60 has a half decay, how many grams

A medical technician is working with the four samples of radionuclides listed in the table below. Initially, each sample contains 18.00 µmol of the radionuclide. First, order the samples by decreasing initial radioactivity. Then calculate how long it will take for the amount of radionuclide in each sample to decrease to 1/4 of the initial amount. sample A B C D symbol 223 88 89 38 61 29 radionuclide 4 Ra Sr Cu Be half-life 11. days 50.0 days 3. hours 53.0 days initial radioactivity ✓ (choose one) 1 (highest) 2 3 4 (lowest) (choose one) ↑ (choose one) ↑ time for amount of radionuclide to decrease to 1/4 of initial amount X days days hours days Ś

A medical technician is working with the four samples of radionuclides listed in the table below. Initially, each sample contains 2.00 µmol of the radionuclide. First, order the samples by decreasing initial radioactivity. Then calculate how long it will take for the amount of radionuclide in each sample to decrease to 1/16 of the initial amount. sample A B C D symbol 201 81 137 55 90 38 64 radionuclide 29 T1 Cs Sr Cu half-life 73.0 hours 30.0 years 29.0 years 13. hours initial radioactivity ✓ (choose one) 1 (highest) 2 3 4 (lowest) (choose one) (choose one) V V time for amount of radionuclide to decrease to 1/16 of initial amount hours years years hours

A medical technician is working with the four samples of radionuclides listed in the table below. Initially, each sample contains 7.00 μmol of the radionuclide. First, order the samples by decreasing initial radioactivity. Then calculate how long it will take for the amount of radionuclide in each sample to decrease to 1/32 of the initial amount. sample A B C D symbol 18 9 46 21 89 38 99 42 radionuclide F Sc Sr Mo half-life 2.0 hours 84.0 days 50.0 days 66.0 hours initial radioactivity (choose one) (choose one) (choose one) (choose one) ✓ time for amount of radionuclide to decrease to 1/32 of initial amount hours days days hours

A medical technician is working with the four samples of radionuclides listed in the table below. Initially, each sample contains 1.00 µmol of the radionuclide. First, order the samples by decreasing initial radioactivity. Then calculate how long it will take for the amount of radionuclide in each sample to decrease to 1/4 of the initial amount. sample A B C symbol 60 27 241 95 203 82 32 15 radionuclide Co Am Pb P half-life 5.0 years 432. years 2. days 14. days initial radioactivity ✔(choose one) 1 (highest) 2 3 4 (lowest) (choose one) ŵ (choose one) ↑ time for amount of radionuclide to decrease to 1/4 of initial amount X years years days days Ś

A medical technician is working with the four samples of radionuclides listed in the table below. Initially, each sample contains 18.00 μmol of the radionuclide. First, order the samples by decreasing initial radioactivity. Then calculate how long it will take for the amount of radionuclide in each sample to decrease to 1/32 of the initial amount. sample A B с D symbol 179 73 91 39 103 46 59 26 radionuclide Ta Y Pd Fe half-life 2.0 years 59.0 days 17. days 45.0 days initial radioactivity (choose one) (choose one) (choose one) ✓ (choose one) ✓ time for amount of radionuclide to decrease to 1/32 of initial amount X years days days days

A medical technician is working with the four samples of radionuclides listed in the table below. Initially, each sample contains 14.00μmol of the radionuclide. First, order the samples by decreasing initial radioactivity. Then calculate how long it will take for the amount of radionuclide in each sample to decrease to 1/132 of the initial amount.