We all know that for an ensemble of particles we can use the exponential decay law. However, the problem I am working on requires to look at nuclei from an atomic perspective. Wikipedia says that this is a stochastic process on the atomic level. I do not have much knowledge of stochastic calculus so I would need help here.... Suppose we have a bunch of nuclei which are decaying. I wish to know a distribution function for the time in which a nuclei from the bunch would decay. How do I do this?