Does the period table appear doubled? Two variants of division of elements into two subsets. Internal and secondary periodicity

Imyanitov, N. S.

doi:10.1007/s10698-018-9321-z

Cited by 9 publications

(7 citation statements)

References 45 publications

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“…The appearance of the kainosymmetric 2p, 3d, and 4f shells every second period causes the secondary periodicity with the scandoid and lanthanoid contractions of the effective atomic bond radii. Many parameters of the elements and their atoms derived from the individual chemical observations can be approximated as expansions in terms of the number of ℓ-valence electrons (Imyanitov, 2019a , b ) and in terms of 1/ Z = Z −1 (Layzer, 1959 ), at least within non-relativistic quantum chemistry.…”

Section: Atypical Periodicitiesmentioning

confidence: 99%

Understanding Periodic and Non-periodic Chemistry in Periodic Tables

et al. 2021

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The chemical elements are the “conserved principles” or “kernels” of chemistry that are retained when substances are altered. Comprehensive overviews of the chemistry of the elements and their compounds are needed in chemical science. To this end, a graphical display of the chemical properties of the elements, in the form of a Periodic Table, is the helpful tool. Such tables have been designed with the aim of either classifying real chemical substances or emphasizing formal and aesthetic concepts. Simplified, artistic, or economic tables are relevant to educational and cultural fields, while practicing chemists profit more from “chemical tables of chemical elements.” Such tables should incorporate four aspects: (i) typical valence electron configurations of bonded atoms in chemical compounds (instead of the common but chemically atypical ground states of free atoms in physical vacuum); (ii) at least three basic chemical properties (valence number, size, and energy of the valence shells), their joint variation across the elements showing principal and secondary periodicity; (iii) elements in which the (sp)8, (d)10, and (f)14valence shells become closed and inert under ambient chemical conditions, thereby determining the “fix-points” of chemical periodicity; (iv)peculiar elements at the top and at the bottom of the Periodic Table. While it is essential that Periodic Tables display important trends in element chemistry we need to keep our eyes open for unexpected chemical behavior in ambient, near ambient, or unusual conditions. The combination of experimental data and theoretical insight supports a more nuanced understanding of complex periodic trends and non-periodic phenomena.

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Section: Atypical Periodicitiesmentioning

confidence: 99%

Understanding Periodic and Non-periodic Chemistry in Periodic Tables

et al. 2021

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“…[7] In recent decades, various excellent, chemically oriented reviewsh ave been published by Kaupp, Huheey,a nd others. [8][9][10][11][12][13] Thereby,t he macroscopic chemical observations were realized as empirical trends and qualitatively rationalized at the AO level.…”

Section: Radial Node Effect and Core Screeningmentioning

confidence: 99%

“…The unique chemical behavior of the 2p elements of the second period of the table of elements, in particular of Bt oF , is well known. [1][2][3][4][5][6][7][8][9][10][11][12][13] Yet, this chemical insight still needs better physicalr ationalization, and better integration into the chemical curricula.W eh ere present ac omprehensive analysis of the nsp valence atomic orbitals (AOs) of the p-blocke lements, that is, of the canonical orbitals from Hartree-Fock or Dirac-Fock or Kohn-Sham levels of theory;w hich simulatet he observable spatial and energetic changes in physical ionization and excitation processes.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Uniqueness of 2p Elements in Periodic Tables

Wang

Szentpály

et al. 2020

Chemistry A European J

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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(ns) ≪ r(np) 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.

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“…In particular the s-block has on the side of lower Z values, along the noble gas 'backbone', the p-block with largely different properties, while on the side of higher Z values, there is a p-, d-or f-block on the inner, middle or outer part of the spiral, respectively, with smoothly varying property values, as sketched on the Abstract Fig. The valence s and p orbitals are energetically comparatively near (see below) so that the elements of conventional groups 1 and 2 and 12-18 form a joint sp block of elements, from the chemical point of view, with smoothly varying properties [58,[61][62][63][64]. The d and f blocks appear inserted in the heavier sp rows after group 3.…”

Section: Combination Of the Two Concepts Of Order And Similarity Givementioning

confidence: 99%

“…13 and Refs. [62][63][64]186]). The reason is the energetic neardegeneracy of the ns and np orbitals ( Fig.…”

Section: The Grand Picturementioning

confidence: 99%