Question

A sample contains 10 g of a radioactive isotope. How much radioactive isotope will remain in the sample after 2 half-lives?

A. 7.5 g
B. 5.0 g
C. 2.5 g
D. 10.0 g

Answer 1

The answer c - Half life how to figure, you first divide it by half then divide than number by half

Answer 2

c) 2.5 g

Step-by-step explanation:

half-life is the time it takes the radioactive isotope to decay to half of the intial sample.

so if the isotope decays to 2 half-lives, it will decay half the intial sample twice.

in the first half-life, the sample will decay from 10 g to 5 g. during the second half-life, the isotope will decay from 5 g to 2.5 g.