one way of showing advanced electron arrangement

So hydrogen would look like:

Helium would look like:

Lithium:

Beryllium:

Boron:

Carbon:

This is not accurate but gives you a visual way of comprehending advanced electron arrangements. If we carried on any further these diagrams would become very complicated. The orbitals or each three-dimensional region of space do allow some overlap but due to the principles of quantum mechanics and negative charges repelling the electrons, still keep in distinct non-clashing probable regions.