There is a well-known electron shielding effect: negatively-charged internal electronic shell screens external shells from positive nuclei, thus increasing their radii.
Thus, 2S orbital radius of Li atom (ground state) should be greater than radius of excited Li2+ cation with single 2S electron.
But is there a reverse influence: from external electronic shells to internal ones? For example, are radii of 1S orbital in Li and Li+ equal, or not?
I am sure there is not a big difference anyway, but this is theoretically interesting. Probably it can be proved by comparision of internal shell ionisation energies of Li and Li+ but I am not sure where to look for appropriate experimental data.
I have some intuitive considerations, while they did not lead me to certain answer:
- Concept of Faraday cage looks to be irrelevant, because electron shells are not literally material conductive shells, but they are filled space regions.
- Shells interpenetrate, thus external shell can a bit force out internal shell from nucleus by increasing electron density in space adjacent to nucleus.
- Classically, internal one of two concentric elastic charged spheres should shrink. If we imagine big spheres, their small areas should interact repulsively as parallel plates. But considered spheres are actually not "big".