Why is Technetium unstable? Technetium is probably the most awkward element of the periodic table for me. It seems to me that Technetium is an exception, in the sense that it doesn't have any stable isotopes, despite having a relatively low atomic number when compared to other unstable elements.

So I thought, maybe there is something special about it. Some exceptional property that causes it to be so unstable with such a low atomic number.

Please tell me. What is it that makes Technetium so unstable?
If you google "why is technetium unstable" you'll see that this question has been around for a while.  Over on physics.stackexchange, it is discussed in Why is technetium unstable?.  

I've read some of what others have posted on this topic and the short answer appears to be: because we have such a poor understanding of the atomic nucleus, there is no answer to this question at this time.  Again, the link above would be a good place to start.  One of the answers (3 upvotes) claims to be an answer.  The selected answer (10 upvotes) says there is no answer.