# How does the vacuum in atoms persist?

From very elementary chemistry I understand that atoms are mostly empty space, with a few tiny little objects whizzing around.

There must then be a vacuum in between these particles. I always thought that nature abhorred a vacuum, and rushed to fill it.

Why doesn't everything clump together in one little ball and get rid of the vacuum? Or are my premises wrong?

• There is no vacuum. The space inside atom is by no means empty; it is occupied by delocalized electrons. Jan 20 '17 at 11:16
• nature abhorred a vacuum, and rushed to fill it Thats not nature, what you're saying is air filling up the vacuum due to pressure differences. Jul 5 '17 at 3:40

I think what you are asking is why electron do not fall in nucleus.

For this you should have general idea of quantum mechanics. Because in the microscopic world nature follows quantum mechanics equations and not classical mechanics equations. Quantum mechanics equations include electromagnetic fields, and their solutions are stable and allow for the existence of atoms, which is what we experimentally observed to start with.

This is general idea of answer given to question physics stack exchange. You can see the detailed answer over in Physics S.E..

This Link will explain diffrent theories which failed to explain why electron do not fall in nucleus.

Well, the glib answer is that nature doesn't abhor a vacuum or anything else. Abhorrence is an emotional state and the universe, as far as we can tell, is not run by emotions. And the space inside the atom has electrons moving through it so one could argue that it's not a vacuum, at which point, we have no abhorrence, no vacuum and no question.

But that doesn't help. Freddy's answer explains why the electrons don't fall into the atomic nucleus, which is basically because of physics that we've only come to understand in the last hundred years. Gases can't get inside an atom because molecules are surrounded by electrons, which are repelled by the atom's electrons; a gas can only fill a vacuum if it can move there.

Without quantum mechanics, it becomes a bit sloppy, but the general principle is easy to grasp:

The nucleus is positive, and surrounded by a number of negative electrons matching the charge of the nucleus.

Once the electrons get pulled too close to the core, they start repelling each other strongly, so there is some equillibrium distance.

Why doesn't the core/nucleus pull in the electrons one by one? Well, they fly "in vacuum", so they get ever faster when they're pulled close to the nucleus. The nuclues can't catch them either, because he has not way to store or discard the huge kinetic energy the electron has. So the whole system is stable, in rather the same way the planets and comets surround the sun.

With a bit of QM, there is the additional point that pairs of electrons fly in a formation ("orbital") that keeps them at an extra distance, and all pairs of electrons have a different formation. That makes sure the whole system stays symmetric and thus stable. Electrons are individualistic, they hate to be indistinguishable from the others. Which of course they are. ;-)

• There's also the fact that electrons aren't little round balls.
– bon
Feb 6 '17 at 13:28
• @bon I thought they were yellow. What's you point?
– Karl
Feb 6 '17 at 13:33
• pairs of electrons fly in a formation is perhaps slightly misleading. They don't fly at all they just exist in space with a probability of being at any one point.
– bon
Feb 6 '17 at 16:16
• The non-quantum mechanics explanation does not work. Planets have no problem crashing into the sun (what we see is the result of most matter falling into the sun, and some matter, planets, having just the right orbit to stay put). Also, the electron repulsion idea fails for one electron systems (e.g. hydrogen atom, which is common in the universe, iopscience.iop.org/article/10.1088/0004-637X/698/2/1467/pdf). Jul 30 at 7:58