We develop the Particle Model of Bond Energy, starting with the energy required to break bonds between two particles interacting via the Lennard-Jones potential. Extending to multi-atom structures, we...We develop the Particle Model of Bond Energy, starting with the energy required to break bonds between two particles interacting via the Lennard-Jones potential. Extending to multi-atom structures, we calculate bond energy by summing pair-wise interactions. For macroscopic systems, we simplify by focusing on nearest-neighbor bonds, estimating the energy needed to separate particles. This model links to macroscopic measures, like heats of vaporization.