The Kinematic Limit of the Periodic Table. Why oganesson is the last and element 119 does not form.

From a single axiom — E_ex + E_unex = mc² = constant — follows a sharp limit on the atomic number. When the exposed energy equals the reserve, the velocity of the 1s electron reaches (√3/2)·c ≈ 0.866c; beyond it no reserve remains to hold the structure. Since v₁s = Z·α·c, the existence condition is Z·α < √3/2, that is Z < 118.68. Oganesson (Z = 118, v₁s = 0.861c) lies just below the limit and therefore exists but lives very briefly; element 119 (v₁s = 0.868c) exceeds it and does not form as an atom. The same limit — seven levels, one hundred and eighteen elements — follows from five independent routes: kinematic, harmonic, logarithmic, from the capacities, and topological. The prediction is binary and falsifiable: a single nucleus of element 119 with the signature of a formed atom refutes the entire framework.