²¹⁰Bi (an isotope of bismuth) has a half-life of 5.0 days. The time for three-quarters of a sample of ²¹⁰Bi to decay is: A) 2.5 days B) 10 days C) 15 days D) 20 days E) 3.75 days

Question

Quizplus · Accepted Answer

Since the half-life of ²¹⁰Bi is 5.0 days, then after 5.0 days half of the sample will remain. After another 5.0 days (total of 10 days), half of what remained will be left, which is equal to a quarter of the original sample. Finally, after another 5.0 days (total of 15 days), half of the remaining quarter of the original sample will be left, which is equal to an eighth of the original sample. Therefore, it takes 10 days for three-quarters (or six-eighths) of the sample to decay.

210Bi (An Isotope of Bismuth) Has a Half-Life of 5

²¹⁰Bi (An Isotope of Bismuth) Has a Half-Life of 5