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Understanding the Uniqueness of 2p Elements in Periodic Tables
Author(s) -
Wang ZhenLing,
Hu HanShi,
Szentpály László,
Stoll Hermann,
Fritzsche Stephan,
Pyykkö Pekka,
Schwarz W. H. Eugen,
Li Jun
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202003920
Subject(s) - valence electron , atomic orbital , periodic table , atomic physics , valence (chemistry) , physics , coulomb , crystallography , electron , chemistry , quantum mechanics
The Periodic Table, and the unique chemical behavior of the first element in a column (group), were discovered simultaneously one and a half centuries ago. Half a century ago, this unique chemistry of the light homologs was correlated to the then available atomic orbital (AO) radii. The radially nodeless 1s, 2p, 3d, 4f valence AOs are particularly compact. The similarity of r (2s)≈ r (2p) leads to pronounced sp‐hybrid bonding of the light p‐block elements, whereas the heavier p elements with n ≥3 exhibit r ( n s) ≪ r ( n p) of approximately −20 to −30 % . Herein, a comprehensive physical explanation is presented in terms of kinetic radial and angular, as well as potential nuclear‐attraction and electron‐screening effects. For hydrogen‐like atoms and all inner shells of the heavy atoms, r (2s) ≫ r (2p) by +20 to +30 % , whereas r (3s)≳ r (3p) ≳ r (3d), since in Coulomb potentials radial motion is more radial orbital expanding than angular motion. However, the screening of nuclear attraction by inner core shells is more efficient for s than for p valence shells. The uniqueness of the 2p AO is explained by this differential shielding. Thereby, the present work paves the way for future physical explanations of the 3d, 4f, and 5g cases.