atoms involves the release of energy and thus is exothermic. The positive values that are listed in tables of E_ea are amounts or magnitudes. It is the word "released" within the definition "energy released" that supplies the negative sign to ?E. Confusion arises in mistaking E_ea for a change in energy, ?E, in which case the positive values listed in tables would be for an endo- not exo-thermic process. The relation between the two is E_ea = -?E(attach).

However, if the value assigned to E_ea is