The half-life of 220Fr is 27.5 sec Calculate the fraction of 220Fr that remains after 1.0 min?

Answer 1

If the half-life of an isotope is 27.5 sec, then one minute is 2.18 half-lives. Radioactive decay is an inverse exponential process, base two, so 2-2.18, or 0.2207 of the original material would remain after one minute. This is half-life mathematics that applies to all radioactive decay. This answer does not confirm nor deny that the half-life of 220Fr87 is 27.5 seconds.