I need the answer to parts a) d) and e)

C.3 a) Sketch a diagram showing how the interatomic force changes with the distance, r, between a pair of atoms. Indicate on your graph the attractive and repulsive regions, the equilibrium separation and the bond energy. b) The interaction potential between a pair of atoms can be modelled by the function: U()=".[()'-()] Explain the physical origin of the terms in the square brackets. c) The expression given is for an ionic solid. Explain how the terms would differ for a substance such as argon. d) By deriving an expression for the force between the atoms, determine an expression for the equilibrium separation ro. e) Determine an expression for the separation, "', at which the atoms experience the maximum attractive force