I have read in many science popularizing articles that atoms are mostly empty space but on more research I have found that that is not the case since what interacts generally with the surrounding is the cloud of electrons or more precisely the roaming electrons which have a non-zero probability of being anywhere in principle.

This explanation is not clear to me.

Consider a hydrogen atom. The nucleus is of the order of a few fermis while the elctron on average moves at around 100,000 distances from it. This looks like a lot of empty space.

What is a clear explanation of this?