Mario Rodríguez Peña

El principio de Aufbau (o diagrama de Moeller) es una regla que permite predecir la configuración electrónica de la mayoría de los elementos. Sin embargo, presenta dos limitaciones importantes: - Falla en el orden energético: En los metales de transición, el subnivel s se ioniza antes que el d porque tiene mayor energía. Sin embargo, el diagrama de Moeller los llena en el orden contrario, lo que genera confusión sobre el orden correcto de la configuración electrónica. - Numerosas "anomalías": Existen 20 configuraciones consideradas "anómalas" (como las de Cr, Cu o Nb), que suelen presentarse como excepciones que deben memorizarse, en lugar de interpretarse como consecuencia de leyes físicas subyacentes. El Principio de Construcción surge para integrar estas discrepancias en un único marco predictivo. No sólo identifica correctamente el orden del electrón diferenciador, sino que también reproduce el orden real de las energías de los subniveles, reduciendo las excepciones únicamente a dos elementos químicos.

The Aufbau principle is used to predict electron configurations and to rationalise the block structure of the periodic table/spiral, yet it suffers from 2 main limitations, the inability to predict 20 “anomalous” configurations and reflect the true order of subshell energies, especially in the “d” and “f” block elements. This work introduces the Construcción principle, a unified framework that simultaneously accounts for both the ordering of differentiating electrons between successive elements and the energy of subshells, thereby predicting the observed electron configurations throughout the periodic table/spiral. This principle also incorporates relativistic stabilisation of s subshells in heavy elements. Moreover, 2 special filling rules are proposed to explain deviations from standard filling: (1) preferential occupation of larger and diffuse subshells by intraorbital repulsion at “d” and “f” block onsets, and (2) stabilisation of half-filled subshells through electron exchange. Prior to formulating these rules, the composition of Group 3 is critically examined using chemical and electronic evidence supporting the inclusion of lutetium and lawrencium in this group, thereby avoiding an artificial interruption of the “d” block against the filling rules. Accordingly, lanthanum and actinium should be regarded as the “anomalous” beginning of the “f” block, filling a d subshell instead of an f one in the formulation of Rule 1. Application of the Construcción principle, including its 2 special filling rules, reduces the number of “anomalous” configurations to only 2, palladium and thorium, yielding correct predictions of electron configurations and consequently, a clear periodic classification.

There are 2 main problems with the current periodic table: artificial breaks from a given noble gas to the next alkali metal (along with the common protrusion of the “f” block) and hydrogen placed in the alkali group, although this gas also exhibits halogen properties. This paper proposes arranging chemical elements in a square spiral with hydrogen at the centre. This element is also above lithium but passes above fluorine to connect with helium, representing its dual alkali and halogen nature effectively. Then the spiral moves outwards in a counter-clockwise direction, avoiding artificial breaks and following the natural direction of reading for the “s” and “p” blocks elements placed at the bottom of the spiral. Furthermore, this proposed square spiral improves upon previous Janet´s and Benfey´s representations with a more regular shape to draw, an effective depiction of the dual nature of hydrogen, and easily identifiable orbital blocks without the need for protrusions.