Grundlagen der Chemie /

2009

Int. J. Quantum Chem.

Basic questions on the periodic system (PS) of chemical elements are still under discussion. Several common misconceptions will be resolved. The word "chemical element" comprises more than two concepts. The PS can be rationalized on a quantum chemical basis, namely with the aid of four concepts: (1) electron configurations of bonded atoms, (2) realistic sequences of orbital energies, (3) spatial extension of valence and Rydberg orbitals, and (4) energy gaps above the closed 1s 2 and np 6 shells (n ϭ 2-6). The PS of known elements cannot be naively extrapolated. The common discussion of the PS in textbooks of general, inorganic, and physical chemistry needs revision.

Section: Elements and Electron Configurationsmentioning

confidence: 99%

Some solved problems of the periodic system of chemical elements

2009

Int. J. Quantum Chem.

Symbol der Chemie: Das Periodensystem der chemischen Elemente im jungen Jahrhundert

2009

Angewandte Chemie

Auf dem Prüfstand: Das Periodensystem der Elemente (PSE) wird seit kurzem theoretisch besser verstanden. Die großen Energielücken oberhalb der Edelgasschalen 1s2 und np6 (n=2–6) drängen dem ganzen PSE eine Periodizität auf, und mit Reihe 7 ist das PSE komplett. Es zeigt sich, dass die Elektronenkonfigurationen freier Atome chemisch irreführend sind und die (n+l)‐Regel ein Beispiel für die „Erfindung von Tatsachen“ auch in den harten Naturwissenschaften ist.

Icon of Chemistry: The Periodic System of Chemical Elements in the New Century

2009

Angew Chem Int Ed

A closer look: A deeper theoretical understanding of the multifaceted periodic system of elements (PSE) has been achieved in recent years. The large energy gaps above the noble gas shells 1s(2) and np(6) (n=2-6) impress periodicity onto the whole PSE, which is complete with Period 7. The electron configurations of unbound atoms are chemically misleading. The common n+l rule is an example of the "invention of facts" even in the hard sciences.