The one-electron term of the Breit–Pauli Hamiltonian multiplies this quantity to a spin–orbit interaction term over a double summation. Using the “self-consistent field” method, this quantity equals the ratio of the expectation for the radius of a hydrogen orbital to that of a hydrogen-like orbital. This quantity multiplies radius in the exponential term of a Slater-type orbital. Factors of 0.30 and 0.35 (10[1])for various orbitals are used to calculate this quantity by Slater’s rules. (-5[1])This quantity is divided by the square of covalent radius to obtain the Allred–Rochow electronegativity. (-5[2])Shielding from inner-shell electrons decreases this quantity (10[1])below the atomic number. For 10 points, name this quantity that roughly describes the electric force experienced by an electron in an atom, denoted “Z-sub-e-f-f.” ■END■ (10[1]0[2])