Chapter 17

Write a nuclear equation for positron emission by each nuclide. (a) Co-55 (b) Na-22 (c) F-18

Write a partial decay series for Th-232 undergoing these sequential decays. $$ \alpha, \beta, \beta, \alpha $$

Suppose you a have a 100,000-atom sample of a radioactive nuclide that decays with a half-life of 2.0 days. How many radioactive atoms are left after 10 days?

A patient is given 0.050 mg of technetium-99m (where m means metastable—an unstable but long-lived state), a radioactive isotope with a half-life of about 6.0 hours. How long until the radioactive isotope decays to 6.3 * 10-3 mg?

Radium-223 decays with a half-life of 11.4 days. How long does it take for a 0.240-mol sample of radium to decay to 1.50 * 10-2 mol?

One of the nuclides in spent nuclear fuel is U-234, an alpha emitter with a half-life of 2.44 * 105 years. If a spent fuel assembly contains 2.80 kg of U-234, how long does it take for the amount of U-234 to decay to less than 0.10 kg?

One of the nuclides in spent nuclear fuel is U-235, an alpha emitter with a half-life of 703 million years. How long does it take for the amount of U-235 to reach one-eighth of its initial amount?

A radioactive sample contains 2.45 g of an isotope with a half-life of 3.8 days. How much of the isotope in grams remains after 11.4 days?

A 68-mg sample of a radioactive nuclide is administered to a patient to obtain an image of her thyroid. If the nuclide has a half-life of 12 hours, how much of the nuclide remains in the patient after 4.0 days?

Write the nuclear equation for the fusion of two H-2 atoms to form He-3 and one neutron.