Periodic Table
T-Shirts & more
from the

Merch Store

previous home next

The INTERNET Database of Periodic Tables

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

Use the drop menus below to search & select from the more than 1300 Period Tables in the database: 

  Text Search:       

The 10 Periodic Tables most recently added to the database:

2023   Bala's Shape of the Periodic Table
1936   Van Wert Periodic table (after Guertler-Leitgebel)
2023   Chemdex: Valence & Oxidation Number Trends
2023   Holistic View of Metals & Nonmetals: Exploded View
2023   Semicircular Hybrid Chart of the Nuclides
2023   Six Stages of The Convergence of The Periodic System
2023   Kudan's Periodic System
1900   History of the Discovery of the Group 18 (erstwhile Group 0) Elements
2023   Element Names: The Etymology of The Periodic Table
2007   Seeger-Quadbeck Periodic Table

Year:  2023 PT id = 1291

Bala's Shape of the Periodic Table

Gavin J. Bala has produced a nice and detailed look at The Shape of The Periodic Table (.PDF) that reviews the science:

Top of Page

Year:  1936 PT id = 1290

Van Wert Periodic table (after Guertler-Leitgebel)

Van Wert LR, An Introduction to Physical Metallurgy, McGraw-Hill, New York, 1936, pp 17. Van Wert says the periodic table is after "Guertler-Leitgebel", which is presumably Guertler WM & Leitgebel M 1929, Vom Erz zum metallischen Werkstoff: Leitlinien und Rüstzeug der metallurgischen und metallkundlichen Wissensgebiete, Akademische Verlagsgesellschaft, m.b.H., Leipzig

From René Vernon who writes:

In this almost symmetrical presentation, Van Wert divides the periodic table metals into:

Strongly Electropositive:       Groups 1 to 3, Ln
High-melting Heavy Metals:   Transition metals
Low-melting Heavy Metals:    Post-transition metals

If the 15 Rare Earths had been shown as 14, and moved one cell to the left we would have a perfectly symmetrical table.

Elsewhere (p. 38) Van Wert refers to the noble metals as follows:

"With respect to corrosion, the noble metals — gold, the platinum metals, and to a less degree, silver — are in a class by themselves. They are comparatively chemically inert to all common corrodents; only silver is appreciably attacked by sulphur gas."

Van Wert's table also refers to non-metals and to inert gases. On page 7 mention is made of the metalloids:

"There are a few elements, also, that partake of the nature of both metals and nonmetals, under many—indeed, under most—conditions they seem metallic enough, but on occasion their behavior is decidedly nonmetallic. These metalloids, as they are sometimes called, add a further difficulty in the attempt to frame a satisfactory definition of the metallic state."

By 1936, it was known that metalloids had a predominately nonmetallic chemistry (Newth 1894, pp. 7??8; Friend 1914, p. 9). So, on the nonmetal side of house are metalloids; "nonmetals"; and noble gases. Separating out the halogens from the nonmetals yields: metalloids; "nonmetals"; halogens; noble gases.

The net result is four types of metals and four of nonmetals = more symmetry.

Top of Page

Year:  2023 PT id = 1289

Chemdex: Valence & Oxidation Number Trends

From Mark Winter's review paper Chemdex: quantification and distributions of valence numbers, oxidation numbers, coordination numbers, electron numbers, and covalent bond classes for the elements Dalton Trans., 2024,53, 493-511

The images below show the Valence number (VN) and oxidation number (ON) proportions as percentages for the elements; and Periodic tables displaying valence number proportions (%). (There are few data for Pm and no data for Fr and elements beyond Es.)

The position of H and the group numbers are addressed in the paper.

Top of Page

Year:  2023 PT id = 1288

Holistic View of Metals & Nonmetals: Exploded View

From Organising the metals and nonmetals: An update by René Vernon from the chemrxiv preprint server.

Rene writes:

Abstract: This paper updates my 2020 article, Organising the metals and nonmetals in which I advocated for parsing the periodic table into four kinds of metals and four of nonmetals. This framework is retained and updated, and augmented with some additional chemistry-related and philosophical observations.

Top of Page

Year:  2023 PT id = 1287

Semicircular Hybrid Chart of the Nuclides

Nawa Nagayasu has produced a new version of the Segrè Chart of the Nuclides.

Nawa writes:

"The chart has the number of neutrons on the [curved] horizontal axis and the number of protons (atomic number) on the vertical axis. I used the IAEA colour coding [scheme]. JAEA's half-life ranks are indicated by simple numbers, not rounded frames.

"In order to fit the whole chart into a semicircle, the axis representing the number of neutrons was made a spiral-like curve. For clarity, the number of neutrons is shown in the middle of each curve."

Yuri Oganessian has commented:

"Nawa Nagayasu is an original and talented designer. After all, it is not easy to work with 118 elements, but now also with isotopes, of which there are more than 3000. The fan design looks attractive and this is very important. This will make people, especially school age, guess the numbers that are written there. So they will gradually delve into the content of the Table, a truly brilliant creation."

Click image to enlarge

Top of Page

Year:  2023 PT id = 1286

Six Stages of The Convergence of The Periodic System

Bran, A.M., Stadler, P.F., Jost, J. et al. The six stages of the convergence of the periodic system to its final structureCommun Chem 6, 87 (2023).

Abstract (abridged):

"We show, by analysing the space between 1800 and 2021, that the system has converged towards its current stable structure through six stages, respectively characterised by the finding of elements (1800–1826), the emergence of the core structure of the system (1826–1860), its organic chemistry bias (1860–1900) and its further stabilisation (1900–1948), World War 2 new chemistry (1948–1980) and the system final stabilisation (1980–)."

Periodic tables representative of each period in history. Families of similar elements (sets sharing colour) shown in each table summarise the patterns and do not necessarily imply continuity nor simultaneity of the families throughout the period:

Top of Page

Year:  2023 PT id = 1285

Kudan's Periodic System

From Pavel V. Kudan, a specialist in mass-spectrometry and identification of compounds, who suggests new periodic table based on new formulation of the periodic law.

See also:

Kudan's Periodic Law (Helix Form)

Genoma de la Materia

Click the image to enlarge.

Top of Page

Year:  1900 PT id = 1284

History of the Discovery of the Group 18 (erstwhile Group 0) Elements

John Marks has provided a concise history of the discovery of the Group 18 elements and the element name"Nitron/Radon".

Radioactivity was discovered by Becquerel in 1896 and the Curies noted transferred radioactivity rather like the induction of electric or magnetic charge. Radon was discovered in 1900, by Dorn in Halle; Rutherford discovered thoron in 1899; and Debierne discovered actinon in 1903. The time-line is:

So niton (from Latin nitens = shining) was noticed by the Curies in 1899 as an emanation from radium. That same year Rutherford noted an identical emanation from thorium, and in 1903 Debierne discovered the same emanation from actinium. All three ('radon', 'thoron' and 'actinon') were identified as an element by Ramsay in 1904 and characterized by him in 1909.

Ramsay named the element niton after its most prominent property viz. that it glowed in the dark.

With the introduction of Soddy's isotopes, it became clear that: thoron was Nt-220, radon was Nt-222 & actinon was Nt-219.

There are natural traces of other isotopes (e.g. Nt-217, Nt-218) from beta disintegration of astatine. So "radon" was just one isotope of niton.

The foregoing history of niton is uncontroversial and the name niton, Nt, for Z = 86 dates at least from Professor Young´s textbook of stoichiometry in 1908.

In 1912, the name 'niton' was adopted by the International Commission for Atomic weights. Rydberg's PT of 1913 has Nt as the last inert gas, as does Irving Langmuir's PT of 1919, Niels Bohr's PT of 1922, GN Lewis's PT of 1923 and even the CRC's Handbook of Chemistry and Physics in 1924.

John Marks concludes:

"Niton, Nt, for Z = 86, was thus established by its discoverers and accepted by the chemistry (and physics) establishment. Radon, Rn, is an error perpetuated by IUPAC [amongst its many sins].

"Radon is an isotope. We do not refer to hydrogen as 'protium', so why are we referring to niton as 'radon'?"

Top of Page

Year:  2023 PT id = 1283

Element Names: The Etymology of The Periodic Table

An excellent video by RobWords about the names of the chemical elements and how they came about:

Top of Page

Year:  2007 PT id = 1282

Seeger-Quadbeck Periodic Table

Seeger-Quadbeck H-J 2007, World of the Elements Elements of the World, Wiley-VCH, Wienheim, inside cover.

René Vernon, who provided the graphic, writes:

"An example of a rarely seen 32-column table. The categorisation scheme is interesting.

Top of Page

previous home next
What is the Periodic Table Showing? Periodicity

© Mark R. Leach Ph.D. 1999 –

Queries, Suggestions, Bugs, Errors, Typos...

If you have any:

Suggestions for links
Bug, typo or grammatical error reports about this page,

please contact Mark R. Leach, the author, using

This free, open access web book is an ongoing project and your input is appreciated.