Imagine this to be an atom: [ + ]
The plus represents a proton and the brackets the region surrounding it. We can imagine the region to extend to infinity.
The probability of finding the electron is somewhere in this region and rapidly decreases as one moves away from the proton.
But we know that electrons can actually leave an atom and land up on another atom somewhere else. Examples are cathode ray tubes and fire.
Interestingly, what happens to electrons that don't manage to land up anywhere? If they do land, we know they create ions out of whatever atoms they land on- guess that makes the cathode more saltish and the plasma screen more saltish too...as time goes by?
Anyway, what is plasma?