"But the bigger effect is relativistic. That’s actually a notable example of Paul Dirac being completely wrong about something in physics – he had stated back in 1929 (PDF here if you’re up for it!) that relativistic corrections to quantum mechanics were of “no importance” because they would apply only to very high-speed particles (that is, those moving at an appreciable fraction of the speed of light). But as it turns out, the inner electrons of the heavier elements are moving at such speeds (they get faster as the positively charged nucleus gets bigger and more charged), and this has effects out to the chemically important outer electrons as well. For one thing, relativistic particles are heavier, and this actually shrinks the atomic radius of the heavier elements still more and has complex effects on the various orbitals."
So basically they both seem to act like their larger scale selves, but in this case affecting physical characteristics of atoms. Special relativity is going to make the electrons more heavy and thus change their ionization energies and interactions with other atoms and energy. Gravity is going to affect their physical geometries? Idk.
But this reminds me of muonic atoms. I wonder if there’s some sort of point where the periodic table of electrons and protons/neutrons starts to mirror its lower energy self with heavier muon atoms.
Just thinking in a text box here, don’t kill me please...
Edit:
The muon to electron mass ratio is about 206 for a square root of about 14.4.
I found an equation that says the energy of that electron is on the order of 1/L^2 so to get muonic effects for the electron the box size of the bound electron, L, needs to decrease by about 1.5 magnitude.
"But the bigger effect is relativistic. That’s actually a notable example of Paul Dirac being completely wrong about something in physics – he had stated back in 1929 (PDF here if you’re up for it!) that relativistic corrections to quantum mechanics were of “no importance” because they would apply only to very high-speed particles (that is, those moving at an appreciable fraction of the speed of light). But as it turns out, the inner electrons of the heavier elements are moving at such speeds (they get faster as the positively charged nucleus gets bigger and more charged), and this has effects out to the chemically important outer electrons as well. For one thing, relativistic particles are heavier, and this actually shrinks the atomic radius of the heavier elements still more and has complex effects on the various orbitals."