Are Sargent-Welch Periodic Tables Up to Date?
Yes. All tables include the most recently discovered elements (114, 116) and the most recently approved element names for elements 106 - 109. Elements 113, 115, 117 and 118 have not yet been observed and are either missing on the table or are in very light type to indicate their current status.

Why are Column Headings in your Periodic Tables Reversed?
Column headings conform to the latest recommendations of the International Union of Pure and Applied Chemistry (IUPAC). Using these recommendations, titanium would be a IV-A element. An older formalism (obsolete in 1986) showed titanium as a IV-B element. Some textbooks continue to use this older formalism. The IUPAC has now recommended that columns be numerically labeled from 1 to 18 to minimize confusion over the A/B column headings (Chemical & Engineering News, January 27, 1986).

Do Sargent-Welch tables meet New York State Requirements?
Yes. The chart WLS18805-80 meets the New York requirements and is fully updated.

What sources do you use to compile these tables?
The atomic weights are those recommended by the IUPAC (1). The element names also conform to IUPAC recommendations, including generic names for elements having atomic numbers 110 and above where formal names have not been approved (2). Electron configurations are from "Atomic Spectctroscopy", by W. C. Martin and W. L. Wiese, in Atomic, Molecular & Optical Physics Handbook", G> W. F. Drake, ed., AIP Press, 1996

• Pure and Applied Chemistry, 71, 1593 (1999)
• Pure and Applied Chemistry, 51, 381 (1979)

Thermochemical and other data for these charts have come from several sources, including:

• J. D. Cox, D. D. Wagner, V. A. Medvedev, CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, (1989)
• CRC Handbook of Chemistry and Physics, 80^th Edition, CRC Press (1999)
• Dictionary of Inorganic Compounds, Chapman & Hall, London (1992)
• Touloukian & Ho (Eds.), Thermophysical Properities of Matter, IFI/Plenum Corp. (1970)

Why do the values for the atomic radius vary from my textbook?
The values listed on our charts are those for the atom in free space, under no extraneous influence. These values will be different from van der Waals, covalent or ionic radii. Calculations of the atomic radius have resulted in different values over the years. We have standardized on the values reported by C. Froese-Fischer, Atomic Data, 4, 305 (1972)

Which Periodic Table is best for Advanced Studies?
We recommend WLS-18805-50 (wall chart) and the same chart in 8-1/2 x 11 inch notebook form (WLS-18806). The wall chart is available in English and French, and the notebook charts in English, French and Spanish. These charts include the most data and are two sided.

Which Periodic Table is best for introductory work?
We recommend either WLS-18808-30 or WLS-18808-45. Both tables show the element name, atomic weight and atomic weight as major items with the table WLS18808-30 having common valences shown also.

Do you have Periodic Tables on Spring Rollers?
Due to the ligh cost of this material, the only periodic table abvailable on spring roller is WLS18805-70R. It is identical to the table WLS18805-70 except it is printed on Kimdura, a material that can be rolled.

Can I copy these tables for use in my classes?
No. Sargent-Welch periodic tables are copyrighted and cannot be copied without permission. We will grant limited copying privileges in special circumstances, for example a single student with special needs. Should you feel that such a situation exists, contact the Periodic Tables Department at Sargent-Welch (email chemistry@sargentwelch.com) explaining the situation and asking for limited reproduction rights.

I think I found an error on your Periodic Table. What do I do?
Send an email to chemistry@sargentwelch.com giving the chart's catalog number, the copyright date (usually at the lower left of the chart) and a detailed description of the item that you think is in error along with the value that you think is correct (a reference would help also). We spend a great deal of time researching and proofing these tables, and if a true error slips through we wish to know about it. True errors can take two forms: a spelling error (Ex. Flourine, not Fluorine) or a completely wrong value (the atomic radius of Mn was shown once as 7.39, not 1.39). Minor differences between compilations do not qualify as true errors.

Sargent-Welch offers a $25.00 gift certificate to the first person finding a true error on a table.

What happened to element 118?
The discovery of element 118 was announced by researchers at the University of California in 1999. In mid-2001 they retracted the discovery, after reviewing all their experimental data and deciding that they had not seen evidence of the element's formation after all. Sargent-Welch charts printed in 2000 and 2001 have the element in black type, indicating the discovery. Charts printed in 2002 will show the element 118 symbol in light gray type to show that the element has not been observed.