An example of the intuitive, independently developed application of the approach along that lines has been presented by Ordon and Komorowski on the ground of conceptual Density Functional Theory (cDFT). The Hohenberg and Kohn theorem 2 on the electron density and the existing mathematical apparatus of the DFT have been applied to construction of the DF connectivity matrix for any molecular system in its stationary state. The matrix elements are given as divergence of the atomic Hellmann-Feynman forces and are numerically obtained from the energy Hessian of the system and have strict physical interpretation as the cumulative (or effective ) force constants between any pair of localized nuclei, providing the clear and unique physical measure for the bonding status between atoms situated in a molecular array. Individual bonded atoms have been characterized accordingly: the diagonal terms of the DFT connectivity matrix reflects the valence of the atom in a molecule and the variation of the elements of the DF connectivity matrix with the reaction progress has been demonstrated to provide the much appealing picture of the modification of the bonding status of atoms along IRC (Reaction Fragility Spectra). The vibrational atomic modes emerging from this analysis, 10 are in close relation to the calculated adiabatic internal vibrational modes AIMO by Kraka et al. Review of many other attempts and approaches to the reaction force constant may be found in the recent papers. The results of the Reaction Fragility spectra have prompted us to developing the theoretical concept even further. We have derived the following gradient theorem from the basic properties of the connectivity matrix: 10,25