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

The relationship among the standard reaction Gibbs free energy Δ G °, the standard reduction potential E °, and the atomic structure parameters of radius, nuclear charge, and isoelectronic orbitals n l is accomplished through the attraction electric force F elec . In relationship with E °, it was necessary to define two new reference scales: E 0 ° with a final state of E ° in the element, which allowed to have a parabolic trend of Δ G ° versus F elec , and E °,0 whose final state is the ion with a more negative charge (e.g., -1, -2, -3). The relationship with Δ G ° is related to the concept of chemical stability, and the relationship with E °,0 is more related to the concept of electronegativity. In relationship with Δ G °, it was necessary to predict the values of possible new cations and noncommon cations in order to find a better trend of Δ G ° versus F elec , whose stability is analyzed by Frost diagrams of the isoelectronic series. This dependence of Δ G ° on F elec is split into two terms. The first term indicates the behavior of the minimum of Δ G ° for each isoelectronic orbital n l, while the second term deals with the parabolic trend of this orbital. For the minima of the configuration n p 6 , a hysteresis behavior of the minima of Δ G ° 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 n p or ( n + 1)s orbitals induces instability of the ion in configurations n s 2 / n d 2 /4f 2 and n d 10 / n d 8 ( n + 1)s 2 , respectively. On the contrary, the stability of the orbitals n p 6 does not depend on the neighboring empty ( n + 1)s 0 orbitals. Both phenomena can be explained by the stability of the configuration of noble gas n p 6 and the n d 10 ( n + 1)s 2 configuration. We have also found that it is possible to increase the reduction potential E °,0 (macroscopic electronegativity), although the electric force F elec decreases because the orbital overlap influences the electronegativity.