For these expressions, energies are expressed in electron volts per k+ –cl– pair, and r is the distance in nanometers. the net energy en is just the sum of the two expressions above. (a) superimpose on a single plot en, er, and ea versus r up to 1.0 nm. (b) on the basis of this plot, determine (i) the equilibrium spacing r0 between the k+ and cl– ions, and (ii) the magnitude of the bonding energy e0 between the two ions.