The fragmentation of the small Xe-n n = 2 - 5 clusters following 70eV electron impact ionization has been investigated in a size selective experiment and simulated using non-adiabatic dynamics. The experimental results show that the clusters strongly fragment to yield monomer Xe+ (more than 90%) and climer Xe-2(+) fragments (the remaining few percent). Trimer Xe-3(+) fragments first occur from the neutral pentamers Xe-5 in a very low yield of approximately 0.3%. The present results are compared with the previous ones for Kr and At clusters. It is shown that the Xe and Kr Clusters exhibit a qualitatively similar behavior with a strong propensity for monomer fragments, while in the At case dimers prevail. The theoretical calculations also reveal a strong fragmentation to the dimer and monomer fragments. However, the dimer Rg(2)(+) is predicted to be the major product for all rare gases (Rg Ar, Kr, Xe). Possible reasons for the discrepancy between theory and experiment are discussed