Question

1.Iodine-131 is administered orally in the form of NaI(aq) as a treatment for thyroid cancer. The half-life of iodine-131 is 8.04 days. How much time is required for the activity of a sample of iodine-131 to fall to 18.8 percent of its original value? Answer in days:

2. Iodine-131 is administered orally in the form of NaI(aq) as a treatment for thyroid cancer. The half-life of iodine-131 is 8.04 days. If you begin with 46.7 mg of this isotope, what mass remains after 10.5 days have passed? Answer in Mg.

3. What is the half-life of protactinium-234 if 16.1 hours are required for the activity of a sample of protactinium-234 to fall to 19.2 percent of its original value? Answer in Hrs.

Answer 1

The radioactive decays are usually of first order reactions .