The Lost Elements

In 1786, Immanuel Kant (1724-1804) wrote “Chemistry can become nothing more than a systematic art or an experimental doctrine, but never a true science, because its principles are merely empirical and… are incapable of the application of mathematics.”

Thus begins an early chapter of The Lost Elements: The Periodic Table’s Shadow Side, by Marco Fontani, Mariagraza Costa and Mary Virginia Orna. 

Merely empirical. A strange phrase given that empiricism is king in today’s scientific endeavors. Show me the empirical data! But experimental data can be very messy, and it turns out that the application of mathematics both helped and hindered the development of the periodic table. Shortly after Kant’s statement, Antoine Lavoisier elevated the importance of measuring data as precisely as possible. Such measurements would be used to distinguish chemical elements, and guide their placement in the periodic table.

Relative mass was a key guiding principle in arranging the periodic table prior to Moseley’s groundbreaking work in 1913, at which point atomic number dethroned mass as the organizing principle. But it was early work by Dobereiner who noticed that elements with “similar chemistry” formed a triad whereby the middle member possessed a relative mass midway between the lightest and heaviest members. (The figure below is taken from the excellent resource, the Chemogenesis WebBook. Dobereiner’s triads are superimposed on the modern periodic table.) It’s a nice example of the application of mathematics, perhaps a step towards turning a systematic art into a true science. This strategy helped Mendeleev to predict the existence of yet-undiscovered elements by noticing such mathematical “holes” in the relative properties of known elements.

In a typical chemistry class, you’d hear of how the periodic table came to be in a cleaned-up story that focuses on the productive discoveries along the way. You hear little of the messiness of actual events; it’s as if the beauty of the periodic table was revealed from on high to a few chemical geniuses who saw the light and shared it with humankind. You hear about the successes but not the failures. The Lost Elements tells the story of the latter. The authors have painstakingly collected information of many no-name people who thought they had discovered new elements, only to find out they were wrong. The path to our modern periodic table is littered with the detritus of elements you’ve never heard of: siderum, australium, erythronium, bithium, nosandrium, wasium, and hundreds more. It’s the shadow side to the story of the periodic table.

The book consists of mostly short vignettes of each “lost” element along with a brief story of its supposed discoverer and why he or she thought something new was found. The stories reinforce the difficulty of measuring tiny quantities and figuring out if those differences made an actual difference! Tiny atoms can’t be seen or handled directly, and therefore ascertaining their properties requires indirect approaches. In the nineteenth century, there were four main approaches: blowpipe analysis, qualitative/quantitative analysis, electrolysis, and emission spectroscopy. We teach the latter three in introductory college chemistry; hardly anyone today has heard of blowpipe analysis.

I’ve mainly browsed and skimmed over the vignettes. Unless you’re very interested in the history of the periodic table, you might find the book boring. The authors have tried to liven things up with catchy vignette titles. I think the cleverest one is: “If Anyone Has a Sheep, Wolfram Will Eat It.” My main take-away from the book was an appreciation of how challenging it can be to separate elements from each other and recognize when you have a pure element that can no longer be further separated. It’s not as easy as it looks, and any separation examples you’ve done in chemistry class are the very easy cases.

Is Vibranium an element? Or is it a compound – an admixture of elements? Could it be found naturally as an ore? Could it be synthesized? Chemists are constantly inventing new materials with interesting properties. Combining elements to make compounds is perhaps even more interesting than separating compounds into their elements. But, if you were to discover a new element, you would have the privilege of naming it! I had my first semester G-Chem class explore this idea for their final project, and it was neat to see their creative ideas. 

Several years ago, I put together an Alien Periodic Table class activity. I’ve now used it multiple times, and I think my students have gained some tiny appreciation of the messiness of how the periodic table came to be. While it incorporates many of the challenges faced by the early scientists (including two episodes where relative mass can trip you up), I have not yet thrown in a “lost element”, but now I’m tempted to try! We’ll see how it goes over with the students.