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The INTERNET Database of Periodic Tables


There are hundreds of periodic tables in web space, but there is only one comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Dr Mark R Leach.

pre 1900 formulations 1900 to 1949 formulations 1950 to 1999 formulations 2000 to 2009 formulations Spiral formulations 3 dimensional formulations
Data mapping periodic tables Miscellaneous periodic tables Books and reviews non-chemistry periodic tables All periodic tables

The 8 Periodic Tables most recently added to the database:

2007     Mechanical Engineer's Periodic Table
1936     Orbital Filling
1946     Achimof's System
2011     Weise's Tetrahedron
2018     First Ionisation Energy to the Standard Form Periodic Table
1905     Gooch & Walker's Periodic System of The Elements
2016     Srivaths–Labarca Periodic Table
1943     Luder's Electron Configuration Periodic Table


2007

Mechanical Engineer's Periodic Table

Avallone EA, Baumeister T & Sadegh AM (eds) 2007, Marks' Standard Handbook for Mechanical Engineers, 11th ed., McGraw-Hill, New York, p. 6-6. Click here for a larger version.

This mech eng PT has a couple of odd features: hydrogen is in Group 17 above fluorine and the lanthanides are split:

Thanks to René for the tip!

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1936

Orbital Filling With Electrons

Students of chemistry are often confused why the orbitals fill with electrons: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6... etc., because the 3d10 seems to be 'out of sequence'.

This 'out of sequence' difficulity is nicely explained if the orbitals are arranged in a slightly different way:

The aufbau principle states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. For example, the 1s shell is filled before the 2s subshell is occupied. In this way, the electrons of an atom or ion form the most stable electron configuration possible.

The order in which these orbitals are filled is given by the n + rule, also known as the Madelung rule (after Erwin Madelung), the Janet rule or the diagonal rule.

Orbitals with a lower n + value are filled before those with higher n + values. In this context, n represents the principal quantum number and ? the azimuthal quantum number. The values = 0, 1, 2, 3 correspond to the s, p, d and f orbital lables.

Julio Gutiérrez Samanez writes:

"I send you the diagram below that reconciles quantum mechanics (diagram for filling the electronic cells) with the Janet table or LSPT. Explaining the duplication of periods with the duplication of the quantum number n, and the introduction of Tao (T) spin of the level or spin of the period, which explains the parity of the symmetric periods."

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1946

Achimof's System

Van Spronsen, on p. 157, says:

"Achimov's system took the form of a cross-section of a pyramid. He based his system on the principle that the lengths of the periods and the analogies in properties between the elements of these periods must be clearly demonstrated."

Achimov EI 1946 Zhur. Obshchei Khim., vol. 16, p. 961

Thanks to René for the tip!

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2011

Weise's Tetrahedron

Dmitry Weise shows how it is possible to go from the Janet [left-step] periodic table formulation, to a tetrahedral formulation.

Dmitry writes:

"Three-dimensional table of the periodic law can be constructed in the form of a tetrahedron having an inner order. A comparison of the tetrahedron shells and the table of elements shows, that one tetrahedron shell corresponds to 4 periods of the 2D table."

Jess Tauber adds:

"The spheres here also aren't labeled, but I explain how they get labeled in the text accompanying the pic.  Each such period (except for s-only, which are obviously simpler) we have a 'switchback' configuration. Like a road going up a mountain back and forth to minimize verticality, or a parachute folded into a pack. There are 8 different ways to do this (4 basic types in 2 chirally opposite mappings). And the original Weise-style non-continuous tetrahedron is just another way to organize half tetrahedra."

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2018

First Ionisation Energy to the Standard Form Periodic Table

There is debate amongst the cognoscenti about the 'best' representation of the periodic table, and how this 'best' formulation can be explained by [rationalized by] quantum mechanics (QM).

Many feel that the Janet PT formulation, the 'Left Step', is the ideal QM PT, but this formulation does not show periodicity very well, and there are issues with the placement of H, He, Be which spill over into questions about their placement in the standard form PT (the periodic table used in classrooms and textbooks around the world).

However, it is possible to get to the conventional standard form PT directly from the first ionisation energy data, where the 1st ionisation energy is the energy required to convert a gas phase atom (M) into its gas phase positive ion plus electron.

M(g)      →       M+(g)     +     e

The process involves:

  • taking the 1st ionisation data plot for the elements H to Xe (Z = 1 to 36)
  • rotate 90° clockwise and stretch
  • move the atoms horizontally into columns

 

Note that a similar logic can be applied to atomic radius and electronegativity data.

However, there are issues about the measurement of atomic radius, because atoms are 'soft at their edges', and gas phase atomic radius is not precisely defined. And, electronegativity is a derived parameter.

 

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1905

Gooch & Walker's Periodic System of The Elements

From a 1905 textbook by Gooch & Walker: Outlines of Inorganic Chemistry (see the Google Books scanned version pp247) comes an early 'right-step' periodic table. The formulation was repoduced in a 1917 textbook (lower image).

Thanks to Eric Scerri for the tip!
See the website EricScerri.com and Eric's Twitter Feed

 

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2016

Srivaths–Labarca Periodic Table

In the new Srivaths–Labarca arrangement, the three main criteria proposed for the position of hydrogen and helium are simultaneously taken into account. Consequently, hydrogen is in between alkali metals and halogens, whereas helium is midway between the noble gases family and the alkaline earth elements.

On the Placement of Hydrogen and Helium in the Periodic System: a New Approach; Martín Labarca & Akash Srivaths, Chemistry: Bulgarian Journal of Science Education, Volume 25, Number 4, 2016

Eric Scerri has critiqued this paper and periodic table here.

Thanks to Eric Scerri for the tip!
See the website EricScerri.com and Eric's Twitter Feed

 

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1943

Luder's Electron Conguration Periodic Table

W.F. Luder's Electron Configuration as The Basis of the Periodic Table, J. Chem. Educ., 1943, 20, 21–26:

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pre 1900 formulations 1900 to 1949 formulations 1950 to 1999 formulations 2000 to 2009 formulations Spiral formulations 3 dimensional formulations
Data mapping periodic tables Miscellaneous periodic tables Books and reviews non-chemistry periodic tables All periodic tables

 

 


Periodic Table, What is it showing?
Binary Compounds

© Mark R. Leach 1999-


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