A sodium atom Na and a chlorine atom Cl will form an ionic bond. Sodium, being a metal, will lose one electron to achieve a stable electron configuration, while chlorine, being a non-metal, will gain one electron to achieve a stable electron configuration. This transfer of electrons results in the formation of a positively charged sodium ion Na+ and a negatively charged chloride ion Cl- . The electrostatic attraction between these oppositely charged ions forms the ionic bond.The bond energy, also known as lattice energy, for sodium chloride NaCl is approximately 787 kJ/mol. This is the energy required to separate one mole of solid NaCl into its gaseous ions.