The potential energy, U, of two atoms a distance, r, apart is U=-(A/r^m)+(B/r^n), where m=2 n=10. Given that the atoms form a stable molecule at a separation of r0= .4nm with a negative energy of -5eV A) Derive the general expression and then calculate A and B. Sketch the resulting force and energy curves. B) Derive the general expressions and then calculate the critical separation at which the molecule breaks (r_max), and the force required to break the molecule (F_max). C) Derive the general expressions and then calculate the stiffness and Elastic Modulus half way before the bond could break. Assume that area of the bond is r0^2