Simulation results are presented for some dynamical processes occurring in the growth of (100) layers of silver. The overlayer dynamics are evolved using a recently developed method that, in the regime where surface diffusion consists of discrete hops, yields classically exact dynamics for an arbitrary interatomic potential. The time-scale limitations of direct molecular dynamics simulations are thus overcome. The Ag/Ag(100) system is modeled using a sophisticated form of interaction potential, similar to the embedded atom method, in which the energy is given by a sum of pairwise interactions plus a term for each atom that depends on the local atomic density. This type of potential includes the many-body terms necessary to describe a variety of atomic environments, such as the perfect fcc metal, free surfaces, vacancies, interstitials, and even the diatomic molecule, but with the computational scaling of a simple pair potential. The present study focuses on some of the dynamics in a single layer of silver: the diffusion and dissociation of clusters of adatoms and vacancies. Some interesting features are observed, including a nonmonotonic decrease in diffusion constant with increasing cluster size, and a roughly constant mean square distance a cluster migrates before dissociation (ejection of a monomer).