I came across a rather dubious question that a teacher had put in a power point. It said something like,"Given a sample of 100 atoms of isotope x, after one half life of the said isotope, how many atoms of the original isotope will be left?"(adsbygoogle = window.adsbygoogle || []).push({});

My answer was that it was a trick question because you cannot know exactly how many atoms will be left. Nuclear decay is a random process and it is only possible to make predictions about the probable mass of a macroscopic sample of an isotope that will decay in a given length of time. Is that correct?

Is it actually possible to calculate the probability that there will be a specific number of the original isotope's atoms left? Say, for example, one says that the expected number is 50, how could one calculated the probability that it would be exactly 50?

I apologize if this question is rather banal, but I am just trying to understand better what is going on. Thanks

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# Nuclear decay of a small number of atoms calculation

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