Chemical matter is made of atoms, which are constructed according to the strange rules of nanophysics. The stability of atoms against radiative collapse was first predicted in the Bohr hydrogen atom model, by the arbitrary imposition of a quantum condition on angular momentum. The Schrodinger equation explains the stability of chemical matter in more detail. An essential additional principle is the Pauli statement that only one electron can occupy a fully described quantum state. This is the "building-up principle" that describes the shell structure of atoms, and the chemical table of the elements.
5.1Chemical Table of
the ElementsThe rules governing the one-electron atom wavefunction W n,l,m,m and the Pauli exclusion principle, which states that only one electron can be accommodated in a completely described quantum state, are the basis for the Chemical Table of the Elements. As we have seen, the strange rules of nanophysics allow 2n 2 distinct states for each value of the principal quantum number, n. There are several notations to describe this situation. The "K shell" of an atom comprises the two electrons of n = 1 (1s 2 ), followed by the "L shell" with n = 2 (2s 2 2p 6 ); and the "M shell" with n = 3 (3s 2 3p 6 3d 10 ). These closed shells contain, respectively, 2, 8, and 18 electrons.In the Chemical Table of Mendeleyev, one notable feature is the stability of filled "electron cores", such as those which occur at Z = 2 (He, with a filled K shell), and Z = 10 (Ne, with filled K and L shells).The situation of a single electron beyond a full shell configuration, such as sodium, potassium, rubidium, and cesium, can be roughly modeled as an ns electron moving around the rare gas core described with an effective charge Z¢, less than Z. That Z¢ is reduced results from the shielding of the full nuclear charge Z by the inner closed shell electrons. It is remarkable that interactions between electrons in large atoms can be in many cases ignored.These rules of nanophysics are believed to account for the schematics of the chemical table of the elements, and, as well, to the properties of chemical compounds. It is a logical progression to expect that the larger aggregations of molecules 5 Quantum Consequences for the Macroworld