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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 1100 Period Tables in the database:

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Periodic Tables from the year 1940:

1940   Gamow [First] Ribbon Periodic Table
1940   Discovery of Astatine
1940   Discovery of Neptunium
1940   Discovery of Plutonium
1940   Hsueh & Chiang's Periodic Properties of the Elements


Gamow [First] Ribbon Periodic Table

George Gamow is well known for his Gamow 1961 ribbon formulation. It appeared in a 1948 book: One, Two, Three... Infinity, but it first appeared in 1940 in 'The Birth and Death of the Sun' (Viking, N. Y.).

Conal Boyce writes:

"The 1940 version of the wound ribbon (in The Birth and Death of the Sun, Figure 12) appears to be the earliest. Gamow re-used it in two editions of another book, 1, 2, 3...Infinity (1948, 1953), as is. He redrew it from scratch for the 1961 edition of 1, 2, 3...Infinity, adding about a dozen new items, notably Np through No, on a new loop. (Unfortunately, in the 1961 version he introduced 4 or 5 goofy errors, including the non-existent 'Fa' for Ga, and a misplaced 'Ba' where Sr belongs, etc.) Most significantly, in another one of his 1961 publications, a book entitled The Atom and Its Nucleus, he swapped the left and right halves of the diagram (see pp. 10-11, Figure 2), so that the noble gas column could be seen as the backbone of the whole structure. He calls it out as such on page 9."

Thanks to Conal and Philip Stewart for the tip!

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Discovery of Astatine


Astatine, atomic number 85, has a mass of 210 au.

Radioactive element.

Astatine was first observed or predicted in 1940 by R. Corson, R. MacKenzie and E. Segrè.

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Discovery of Neptunium


Neptunium, atomic number 93, has a mass of 237 au.

Radioactive element: Np is only found in tiny amounts in nature. Most samples are synthetic.

Neptunium was first observed in 1940 by E.M. McMillan and H. Abelson.

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Discovery of Plutonium


Plutonium, atomic number 94, has a mass of 244 au.

Radioactive element: Pu is only found in tiny amounts in nature. Most samples are synthetic.

Plutonium was first observed in 1940 by Glenn T. Seaborg, Arthur C. Wahl, W. Kennedy and E.M. McMillan.

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Hsueh & Chiang's Periodic Properties of the Elements

Hsueh & Chiang, Periodic Properties of the Elements, J. Chinese Chem. Soc., 5, 5, 253-275. See the PDF.

René Vernon writes:

"A mathematical expression of the periodic law was put forward in 1937 in an article by Chin-Fang Hsueh and Ming-Chien Chiang: J Chinese Chem Soc, 5, 263 (In English.) They derived a property equation from which the numerical magnitude of a property P is related to the atomic number Z of the element in question in terms of valence V, a function of the periodic factor y, the principal quantum number n, and two parameters a and p, which are constants for a given family of elements but different for different families."

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What is the Periodic Table Showing? Periodicity

© Mark R. Leach Ph.D. 1999 –

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