For a na'-ci ion pair, attractive and repulsive energies ea and er, respectively, depend on the distance between the ions r, according to 1.436 7.32 106 for these expressions, energies are expressed in electron volts per na-cl- pair, and r is the distance in nanometers. the net energy en is just the sum of the preceding two expressions (a) superimpose on a single plot ex, er, and ea versus r up to 1.5 nm using matlab. (b) on the basis of this plot, determine (i) the equilibrium spacing ro between the na and cl ions, and (ii) the magnitude of the bonding energy eo between the two ions. (c) mathematically determine the ro and eo, and compare these with the graphical results from part (b).