  The periodic changes in the physical and chemical properties of the chemical
elements are caused by the periodic change of the ionization energies, which
are constant for each element that manifested in the Periodic Table. However,
as has been recently shown the modification of the electromagnetic field in the
photonic crystals gives rise to the modification of the electron
electromagnetic mass. We show that the effect can significantly change the
ionization energy of atoms placed in voids of photonic crystals consisting of
metamaterials with a highly tunable refractive index and voids. The
controllability of these materials gives rise to the controllability of the
ionization energies over a wide range.
