If En is the net bond energy in terms of r (distance) and Eo is the minimum valueof net energy, which statement is/are false? (20 pts) \text { a) }

a t E_{0}: \frac{d E_{N}}{d r}=0 b) ris the equilibrium spacing. \text { c) } a t E_{0}: \frac{d E_{N}}{d r}>0 \text { d) } a t E_{0}: \frac{d E_{N}}{d r}<0 \text { e) } a t E_{0}: \frac{d E_{N}}{d r}=1 \text { f) } a t r_{0}: \frac{d E_{N}}{d r}=1 3. What type of properties is different in the materials below? Your answer shouldbe maximum one line.(10 pts)