Consider the ionic salt, kcl (potassium chloride). the attractive and repulsive energies between the ions k+ and cl depend on the distance r between them according to the following relationships: 5.86x10-6 e, = 1.436 e = r ey = ea +er where the energies are expressed in electron volts (ev) and the distance r is in nanometers (10°m). eis the net potential energy between the ions. (a) using excel, superimpose on a single plot ex, ex, and e, versus r, for r from 0.22nm to 0.5nm. build the spreadsheet first and then plot the functions. hint: use a fine enough interval between r values such that you can see a minimum ex value. (b) on the basis of this plot, determine (i) the equilibrium spacing r, between the k and clions, and (ii) the magnitude of the bonding energy e, between the two ions. (c) mathematically determine the r, and e. values using the equations above and compare these with the graphical results from part (b).