HSU Chemistry Department Periodic Table

The Humboldt State University

Periodic Display of the Elements

Assembled by

Richard A. Paselk & John B. Russell

with the assistance of

William F. Fraser, Deborah A. Paselk, and Marty Reed

Original conception by

Dmitri Mendeleev, Lothar Meyer, and others

Notes:

This display contains specimens of all of the elements that exist as stable, non-radioactive isotopes. The samples represent the most common and/or stable form of each element occurring at one atmosphere pressure and 25 °C. In the case of carbon, two stable allotropes (different forms), graphite and diamond, are present. A silicon wafer, used in manufacturing solid-state electronics, is provided as a second Si sample.

To prevent the samples from reacting with atmospheric components, most of the solid and liquid specimens have been sealed in flasks or vials under inert gas (generally argon). Even so, you will notice some with white or gray powdery coatings. In these cases the elements have reacted with the atmosphere. Frequently this was the case when the samples were opened even though they were “stored under argon” by the manufacturer. Many of these elements or their compounds are extremely toxic and/or difficult to work with, so we chose to use them “as-is.” Replacing them with new samples would have cost (1995) between $30 and $120 each, depending on the element. (rap 1995; rev. 2007)

Origins:

With the modification of the 5th floor of Science A in the late 1980's the Chemistry Department received new facilities funds, some of which Dr. John Russell used to purchase samples of all of the non-radioactive elements not already in the stockroom. In 1990 I was able to win a grant of $600 from the Seventh Annual Humboldt Enrichment Awards Program to have a display case constructed of oak with a "bulletproof" scratch-resistant window by our shop. Once the case was completed we began putting specimens on display, but quickly found many were unstable in contact with the atmosphere. Fortunately the stockroom had a large supply of no longer used small (50mL) florence flasks that could be sealed on our glass lathe. Over a period of time all non-stable sample were sealed under Argon gas in these flasks. When the display was finished we found that two elements had been missed, so I purchased samples of these elements and sealed them under Argon in 50mL flasks. I later added a small Si wafer from IBM via Bill Golden and an uncut diamond I bought in Amsterdam. (rap 12 August 2019)