  We analyze the electronic structure of atoms in the first, second and third
periods using the electronic kinetic energy density and stress tensor density,
which are local quantities motivated by quantum field theoretic consideration,
specifically the rigged quantum electrodynamics. We compute the zero surfaces
of the electronic kinetic energy density, which we call the electronic
interfaces, of the atoms. We find that their sizes exhibit clear periodicity
and are comparable to the conventional atomic and ionic radii. We also compute
the electronic stress tensor density and its divergence, tension density, of
the atoms, and discuss how their electronic structures are characterized by
them.
