Gallium 68 Half Life

If the half-life of Gallium 68 is 68.3 minutes, how many samples of 10.0 mg remain after half-life? 3

Half life Three and a half lives?

68.3 minutes is an extraordinary number. Half-life is the time when half the atoms of the radioactive element fall. So you have 5.0 mg after 1 half-life, 2.5 mg after 2 half-lives, and 1.25 mg after the third half-life.

You can multiply 68.3 3 times and get 204.9 minutes for 10 mg gallium 68 and reduce it to 1.25 mg.

After half the life, half of the substance remains. After two 1/2 minus (1/2 of 1/2). After three 1/2 minus (1/2 to 1/2) minus (1/4 to 1/2). Half of the current amount is lost in every half life.

After the remaining 1.5 mg. After 2, 2.5 mg remains. After 3, 1.25 mg and so on.