In this work the electronic behavior of hydrogen impurities in lanthanum (La), scandium (Sc) and yttrium (Y) matrices is studied. For each one of the systems some fundamental physical properties are determined, as the induced screening electron density, the volume of solution of hydrogen, the solution heat and the variation of the density of electronic states, using the formalism of the density functional theory (DFT) and the jellium model. We propose a new parameterization for the solution heat in terms of the change of total energy of the system, obtaining an excellent agreement with experimental values reported in the literature. One of the main features of this model is that it yields accurate values of those properties of the system which are strongly dependent on the density of free electrons. The results obtained by this method are compared with experimental data available in the literature, as well as with more sophisticated theoretical models. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.