The electronegativity and the hardness are two popular and useful theoretical descriptors of chemistry and physics successfully used by both physicists and chemists in correlating chemico-physical properties of atoms, molecules and condensed matter physics. We have tried to explore the fundamental nature of the hardness and electronegativity of atoms and have observed that their fundamental nature is basically lying in electrostatics and manifest as the electron attracting power emanating from the nucleus of the atom. We have tried to correlate the periodic nature of variation of the electronegativity and the hardness to the electron attracting power of the nucleus from which they are originated and developed. We have developed the formulae for evaluating both electronegativity and hardness and found that they have the direct correlation with the effective nuclear charge of the atoms and hence their periodicity.
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