E = mc2 therefore mass is energy. Mass divided by volume gives you the density and since mass is energy we can call it the energy density.
If it were possible to know the true radius of an atom of a particular element e.g. Aluminum then you could calculate the true volume of that atom. Divide the mass by the volume would give you the energy density for the atom. Since every element has a different mass and volume then each element has its own energy density which is unique to it.
My question is this, If I wanted to make a chart so that it would be possible to make a comparison of energy densitys (on an atomic level) for various elements could I use standard density (g/cm3) chart or would the difference in the crystal structure of each element introduce errors, i.e. some crystal structures may geometrically allow more atoms per unit area then others?
I’m trying to explain this but not sure I have done a good job of it, hope you understand what I’m getting at.