Re: Electron-nucleus attraction

Your reasoning is pretty right. But there is a hidden stage in the argument.
To see what it is, you need to think about the solar system. The sun and
the planets all attract one another with the force of gravitation, but the
planets are not all found clustered in the immediate vicinity of the sun.
(Nor burned up and incorporated into it, which would be more realistic!)
Orbital motion is one way that two particles that attract one another will
nevertheless stay apart indefinitely. The first models of the nuclear atom,
due to Bohr and Summerfeld, used the analogy of a solar system and orbital
motion to describe the structure of such an atom.

But such a structure cannot work for an atom. The reason is fairly subtle. 
If we apply Maxwell's equations of classical electrodynamics to an 
accelerating charged particle, we find that such a particle must necessarily
emit light. For an orbiting particle, the only place the energy to produce
this light can come from is the kinetic energy of orbital motion. So as the
particle orbits, it is accelerating. It must constantly emit light, and drop
into a lower orbit! It will soon spiral into the nucleus.

So while an orbiting system is stable for particles with
gravitational attraction, it is not stable for the seemingly analogous
classical electrostatic attraction! That means that the explanation of a 
stable atom must lie within quantum mechanics. Your attempt using the
Heisenberg uncertainty principle is one of several ways of looking at the
problem, and a quite correct analysis.

It also shows that you have a pretty good understanding of some pretty
tricky Physics. Keep up the good work.

John.