Iodine-131 is used medically to study the activity of the thyroid gland. iodine – 131 has a half-life of about 8 days. this means that approximately every 8 days, half the mass of the iodine decays into another element. if a container held a mass of 64 milligrams of iodine – 131, how much is left after 40 days?

0.002 mg of sample will be left after 40 days.

Step-by-step explanation:

Half life of the iodine-131 == 8 days

Initial amount of iodine-131 == 64 milligrams = 0.064 g

Amount of iodine-131 left after the time of  40 days = N

Decay constant = = ?

N = 0.002004 g = 0.002 mg

0.002 mg of sample will be left after 40 days.

the answer is 62