Can I just correct something, tell me if I'm wrong.
These atoms go on to form elements
an atom is an element, elements are a single atom but different element differs due to the difference in the number of proton, neutrons and electrons. But atoms don't make elements, sub-atomic particals does.
What if one of the elements in our body become unstable, and the only means to survive such a catostrophe is by mutating our body to adapt?
and
For example the unstable particle in our body is carbon. It becomes unstable after an undtermined period of time(my math stinks), because of its half-life to time ratio or something like that.
If the atom is stable, it wouldn't become unstable unless undergone fission or fusion that knocks out an proton or neutron. The unstable ones will try to become stable by emitting an proton etc.
We all have unable stoms in our body, the isotops of the "normal" - stable ones still does the same job as the unstable ones, but they will decay to become stable, and the rate for them to decay to half of their original mass is their half life. Usually they are pretty long, and we'll be long gone before they did, so there's no point to worry. Compare to the amount of radiations we recieve from the environment, they seemed non-important as all. I'm not sure if our body mutate to adapt, but I think it is more like we mutate, and in some cases like cancer it cause problems, but if somehow the condition of the environent changes, if the mutation is an advantage to it, we will survive better than the unmatated ones, and that's how natural selection works. So I think, mutation is does not occur for us to better adapt to certain situations.