Ionic Bonding in NaF: The ionization potential of sodium is 5.14 eV, the electron affinity of fluorine is 3.40 eV, and the equilibrium separation of sodium fluoride (NaF) is 0.193 nm. (a) How much energy is needed to form Na+ and F- ions from neutral sodium and fluorine atoms? (b) What is the electrostatic potential energy of the Na+ and F- ions at their equilibrium separation? (c) The dissociation energy of NaF is 4.99 eV. What is the energy due to repulsion of the ions at the equilibrium separation?