Question

Rank the following species in order of increasing density?

Rank the following species in order of increasing density:

-Si nucleus
-Si electron cloud
-Si atom
-Foil sheet of Si atoms (bulk silicon)

Answer 1

We expect this order of density:

Electron cloud < atom < bulk material < nucleus

Explanation:

The nucleus is certainly the densest thing, packing over 99.9% of the total mass into a tiny fraction of the total volume.

Conversely the electron cloud, with the nucleus taken away, has very little density and would be the lowest density.

Which leaves the overall individual atom and the bulk silicon foil. It looks like both would be the same density, but remember that in bulk solids or liquids atoms tend to overlap and get squeezed a little bit.

We would thus expect the order

Electron cloud < atom < bulk material < nucleus.