Apr 18, 2008
Rebuilding the Periodic Table
The Periodic Table of the elements is a fascinating icon of science. It is incredibly useful and has been exploited and sexploited too in the form of a periodic table of yoga and a sexy PT. It has also been hacked apart, cut and paste into different formats, created as illuminated wall cases, woodworked into furniture, spiralled, spherized, and generally rebuilt in almost every imaginable way ever since Mendeleev first dreamed of laying out his elemental cards according to the periodicity of elemental properties.
Now, in an effort to inspire chemists to reconsider the foundations of the periodic table, chemical philosopher Eric Scerri of the University of California, Los Angeles, is building a new way to classify the chemical elements one step at a time.
Writing in the latest issue of the Journal of Chemical Education (PDF 2008, 85, 585-589), Scerri explains how the periodic table initially arose from the discovery of atomic weight triads but he now suggests that chemists should recognize the fundamental importance of atomic number triads.
This sea change in elemental attitude might enhance the periodic table by classifying the elements at a fundamental level as basic substances. As such, he and his colleagues have developed a new version of the “left-step” periodic table, which looks very different from the conventional PT. In the new layout, with its step-like pattern actinides and lanthanides are no longer relegated to a standalone box, but form the first step of the PT.
Climbing right to the transition metals (Fe, Mn, Ir, Sg et al) on the next step and then to the non- and semi-metals, such as boron carbon, oxygen, silicon etc and finally a step in which the halogens (fluorine, chlorine…), noble gases (neon, xenon…), alkali metals (potassium, sodium…) and alkaline earth metals (beryllium, calcium…) form the final highest step on the right. Hydrogen tops the halogen column and helium crowns the noble gases rather than acting as the outer beacons as with the conventional layout. (Click the graphic for a clearer, full-size view).
“The left step table has been around for some time,” Scerri told me, “but I am modifying it to accommodate two atomic number triads which would otherwise be absent. They are He, Ne, Ar which ceases to exist as a triad in the usually encountered left-step table and H, F, Cl which does not exist either in the conventional medium-long form table or the usually encountered left-step table.”
In the grander scheme of things, whatever form the Periodic Table takes in the future matters not to those of us who sing, so we end with a song, the periodic table song from Tom Lehrer (who was 80 on April 9, 2008 and gets a mention in the Official Google Blog this week), known simply as The Elements.
"Deceived Wisdom: Why What You Thought Was Right Is Wrong" from David Bradley. Available now on 
Dear Roy,
Thanks for your responses. I am often asked why my periodic table has H and He shown in two places. Eric Scerri was the first one who asked me that about three years ago when I emailed him my first version of ADOMAH Table. Philip Stewart even asked me to make up my mind and to choose one of the two locations, when he was preparing his article about Janet for publication in Foundations of Chemistry. I would like to give you some background, so you can see where I am coming from.
Charles Janet was struggling with this question for some time. You can see that his version II periodic table (http://www.meta-synthesis.com/webbook/35_pt/JanetI.jpg) had H and He above F and Ne respectively. However, his Version III periodic table has H and He above Li and Be. He realized that it would be controversial, but he insisted that this is the right position for those two problem elements.
Eric Scerri writes in his book that he believes that only one particular representation reflects chemical periodicity as an objective fact. I happened to believe the same, except I would use word “periodicity”, instead of two words “chemical periodicity”.
Mendeleev’s 1869 Periodic Law states: “The elements, if arranged to their atomic weights, exhibit an evident periodicity of properties.” The term “atomic weights” are now replaced by atomic numbers, but meaning of words “periodicity of properties” are not quite understood because, I argue, word “properties” are mistranslated.
I say that because Russian is my first language. Russian word “svoistva” and English “properties” is not quite the same thing. For example, Russian-English Dictionary by A.M. Taube et al, Moscow Russian Language Publishers, 1978, that I happen to have on my book shelf gives following translation for word “Svoistvo”: characteristic, quality, property. Do you see the difference? I would also add to that list word “attributes”. Therefore, when Mendeleev states “All that I am going to say [about the Periodic Law] must be understood as relating to atoms … not to simple bodies” and Periodic Law “expresses the svoistva of real elements and not of what may be termed their manifestations visually known to us” I understand exactly what he was trying to say. He actually meant that periodicity had to be understood in terms of attributes of the atoms.
I believe, as mathematicians do, in describing things with minimum possible terms. That is, if I can come up with equation that describes some natural process with only two terms, I would not consider optimal equations that describe same thing with three or more terms. On my home page http://www.perfectperiodivtable.com I demonstrated that, based only on Atomic numbers and maximum n+l values, the periodic system, as it is known today can be replicated almost completely, with exception of one problem element, He.
According to Dr. Scerri, elements are defined by their atomic numbers only. He also states in his book that “.. an optimal classification can be obtained by identifying the deepest and most general principles that govern the atoms of the elements, such as n+l rule and by basing representation of the elements on such principles.”
Based on aforesaid I agree with Henry Bent’s statement that “dualistic classifications, such as metal-nonmetal, are not based on any natural law … Because elements, as simple substances, have many properties, they can be classified artificially, in many ways, according, e.g., to density, volatility, hardness, abundance, toxicity, metallic character…”, etc. “Useful though such classifications are in particular instances, they do not lead beyond themselves, to broad generalizations. Consequently, they do not lead to a unique, natural classification.”
In regard to ADOMAH Periodic Table, I have shown one location of H and He, that I consider artificial, in dashed lines and the other location, that I consider natural, in solid lines. I admit that this was done before I reached current understanding of the Periodic Law. Later I decided to keep it this way, just to illustrate, why that common misconception exists. Similarly, I could place Mg in dashed lines next to Zn and Sr next to Yb.
Therefore, per the quote above, your periodic table, useful though in some respects, does not lead to a “unique, natural classification”. And the unique and natural classification I strive to achieve.
Best,
Valery Tsimmerman
10-10-10
I see, Valery, on your Perfect table, that H & He have been repeated.
How do you like the 3D solution on my small table (at http://allperiodictables.com/3d/ )?
One more dimension in a periodic table permits placement of H in multiple conjunctions, as the “Hydrogen Crown” loops (or starts) from the Noble Gases, traverses the Non-Metals, and then touches down to both F and He, all adjacencies for H which have been under scrutiny, and all proposed individually or in tandem by various experts – but only in the 3D AAE are realized simultaneously.
You have studied this aspect extensively, it seems, and I wonder if you think the material I have copied from here and there for the edification of students at
http://allperiodictables.com/aptpages/gridlink/grid09_hydrogen.htm holds water, is to complex, or is sufficient for the new student.
Yes, Valery, as Gell-Mann said “certain negative principles get embedded in science sometimes”, and the objectivity of minds open to improvements are necessary for science.
De Beguyer placed elements in sequence, just as Mendeleev later stated they should be in what became “The Periodic Law”. Also no slave to precedent, Courtine preceded my similar construct by at least 40 years.
Having no knowledge of these previous 3D models, it was the surprising conflict between the Sargent-Welch flattened table and the “Law” that I, with the instincts and objectivity of a museum exhibit designer to provide clarity, went about placing related element data boxes contiguous both vertically and horizontally, avoiding the dozen or so breaks that are unnecessary in a 3D model.
I have no doubt that Dr. Eric Scerri arrived at LSPT (1928) layout independently. I did not mean to question his integrity. I learned a lot from his book “The Periodic Table, Its Story and Its Significance”. In fact, it happened to me also, when I thought that I discovered it in early 2006. It was quite a disappointment when, after extensive search on Internet, I found it here: http://www.meta-synthesis.com/webbook/35_pt/JanetI.jpg. I know at least two more people who came up with the same layout long after Janet. Here is one from 2002: http://www.sciteclibrary.ru/rus/catalog/pages/2804.html. I am little surprised that Journal of Chemical Education did not find those sites while reviewing the article.
I find it fascinating that many different people keep coming up with the same layout again and again. Doesn’t it say something about its objectiveness?
Valery Tsimmerman.
Maybe so but I arrived at this table independently and have a justification for it.