Relationship between the Atomic Structure and Electrochemistry. 1. Electric Force, Standard Reduction Potential °, and Standard Reaction Gibbs Free Energy Δ°.

The relationship among the standard reaction Gibbs free energy Δ°, the standard reduction potential °, and the atomic structure parameters of radius, nuclear charge, and isoelectronic orbitals l is accomplished through the attraction electric force . In relationship with °, it was necessary to define two new reference scales: with a final state of ° in the element, which allowed to have a parabolic trend of Δ° versus , and whose final state is the ion with a more negative charge (e.g., -1, -2, -3). The relationship with Δ° is related to the concept of chemical stability, and the relationship with is more related to the concept of electronegativity. In relationship with Δ°, it was necessary to predict the values of possible new cations and noncommon cations in order to find a better trend of Δ° versus , whose stability is analyzed by Frost diagrams of the isoelectronic series. This dependence of Δ° on is split into two terms. The first term indicates the behavior of the minimum of Δ° for each isoelectronic orbital l, while the second term deals with the parabolic trend of this orbital. For the minima of the configuration p, a hysteresis behavior of the minima of Δ° is found: an exponential behavior from periods 1 and 2 and a sigmoidal behavior from periods 5 and 4 to interpolate period 3. It is also found that the proximity of unfilled p or ( + 1)s orbitals induces instability of the ion in configurations s/d/4f and d/d( + 1)s, respectively. On the contrary, the stability of the orbitals p does not depend on the neighboring empty ( + 1)s orbitals. Both phenomena can be explained by the stability of the configuration of noble gas p and the d( + 1)s configuration. We have also found that it is possible to increase the reduction potential (macroscopic electronegativity), although the electric force decreases because the orbital overlap influences the electronegativity.