Density Functional Theory has proved to be a fast and efficient method for calculating various properties of solid insulating materials. From our studies, we have observed that calculations of the structural and electronic properties of alkali metal hydrides LiH, NaH, KH, RbH and CsH) and alkaline earth metal hydrides (BeH2, MgH2, CaH2, SrH2 and BaH2) reveal the exact problem with the description for these compounds within PBE formulation of generalized gradient approximation (GGA), which is our principal focus.Generally, for the hydrides accurate calculation of the band gap requires...