It seems like an element should have to be stable to be considered an element. This only lasted a few microseconds. Couldn't you put almost any combination of particles together for an arbitrarily short amount of time? What's special about an element?
If you only counted stable substances as "elements", an awful lot of things would have to get a different name. Uranium wouldn't be an element at all, because even U-238 (the most common isotope, more than 99% of the stuff found in nature, http://en.wikipedia.org/wiki/Isotopes_of_uranium) will be reduced by half in a few billion years.
You could set some time limit of half life, below which is considered "completely unstable" and doesn't count, but what purpose would such an arbitrary division serve?
Yes, you can slam particles together in any combination, but the special thing about elements is that, for at least a few microseconds, it didn't need any external force or containment to hold together. A few microseconds is a long time at the subatomic scale.
They are not just particles near each other, but they actually combined into a single particle - an atom.
In the macro world if you put things together, then separate them you get the same pieces back. In the micro world it's not like that - the protons and neutrons combine into a single mixed jumble.
So that's what's special about it, despite it being unstable: at least for a time it was a single particle.
Instability is all about energy, if you release energy by splitting off a particle, it will do so. Guaranteed. If you need energy to do so, it won't. The time it takes to decay is directly proportional to the amount of energy released.
(Another thing that can cause stability is conservation of quantum number like charge and momentum. If it's illegal for a piece to split off, then even if there is a lot of energy, it won't.)
But instability does not imply the atom is somehow less of an atom than another one. It's just an atom at a very high energy level.
I rememebr he says something about higher you go in the periodic table you add more electron to the shell and there is only a finite amount of space in there, and at the time, highest element had all of the slots filled in and then something weird about electron orbit.. ugh and I have watched it just the other day.. but there it is, and all of the videos are very interesting (at least to me)
