[constant thinker]

I was thinking and if you theoretically had a pure substance of any radioactive element would it decay to the same thing? By that I mean after the whole sample decayed to something stable would it all be the same element or would some decay to one element and others to another.

I've tried google searches on radioactive decay but none of it answers my question.

[constant thinker]

Maybe I should rephrase the question. Does uranium always decay into element x? If i have say a pure sample of uranium-235 will the whole sample turn into element x or will some become element x, some element y, and some element z? When you say protons composition do you mean just the number of protons or the protons and neutrons. I know that different elements will decay differently because of the difference in protons, but is it guranteed to decay into 1 element or multiple.

[Mitch]

Yes, it all eventually decays to the exact same thing on a long enough time scale and assuming your Uranium sample contains only one isotope and decays only by alpha decay.

The answer is No, if you factor in the fact that some of the Uranium will undergoe spontaneous fission.

[constant thinker]

Ok thank you. It was a random question that popped into my mind. I figured that given perfect circumstances and you had a pure sample of 1 isotope and no fission took place that given enough time it'd all become the same element. I was not sure though and am in biology at school and do not have a chance to see any chemistry teachers.

[jdurg]

Theoretically speaking, if you had one isotope that only decayed via one method into elements that furthered decayed by only one method, then yes, you'd wind up with one pure isotope of another element.  However, the chances of that happening is slim to none since almost all decay chains of the heavy elements have the chance for some spontaneous fission which completely changes the decay chain.