Hi everyone! I have two questions about radioactive decay that some of you might be able to answer (I'm a mathematician and no physicist by the way). The first one is very general: As I understand it the time at which a single instable atom decays is believed to be a truly random process. But what about the type of decay that occurs? For example if you lookup Technetium-99m in wikipedia it says under Nuclear properties: "Tc-99m decays mainly by gamma emission, slightly less than 88% of the time." and "The remaining approximately 12% of 99mTc decays are by means of internal conversion, resulting in ejection of high speed internal conversion electrons in several sharp peaks (as is typical of electrons from this type of decay) also at about 140 keV" Is it also truly random which type of decay will occur in the same sense it is random when it will occour? Should these values 88% and 12% be valid under all circumstances or are there any environmental factor that are known or at least believed to influence them? For example it is known that observing a single instable atom (testing if it has decayed) will collapse its wave function and in some sense "reset the timer". So an atom that is constantly observed is believed to never decay which means that the decay rate is only true for unobserved atoms. Is there anything that is believed to influence the type of decay as well? (if it even is truly random) My second question is very specific and relates to the mentioned Technetium-99m. Does anyone happen to know where I can find the most accurate chances of it decaying one or the other way that are known from experiments or follow from theory. Do these chances (and also the decay rate) even follow from theory or can they only be found experimentally?