This year marks the 150th anniversary of the development of the periodic table by the most famous Russian scientist of the modern era, the chemist Dmitri Mendeleev. This anniversary has been deemed important enough that the United Nations, and in particular UNESCO (the United Nations Educational, Scientific and Cultural Organization), to declare 2019 as the International Year of the Periodic Table.
Conferences, celebrations, recitations, exhibitions and special editions have emerged to the point that we have been virtually saturated, if you’ll excuse the chemical pun. Perhaps the most important of these events has been the 4th International Conference on the Periodic Table that was held very appropriately in Saint Petersburg, where Mendeleev carried out his groundbreaking work on the periodic table.
This anniversary also gives us the opportunity to reflect on the nature of scientific discovery and the well-known fact that the vast majority of discoveries occur gradually over a period of several years, and very frequently occur almost simultaneously between scientists who may not be in communication with one another. Such was the case with the periodic table, which was “discovered” by at least five scientists before Mendeleev stepped into the frame to tidy things up and to introduce the idea of using the periodic table to predict new elements. Of course everybody likes a winner and it is good to have celebrations of scientific events. But such activities should not blind us to the cumulative development of most of science—contrary, incidentally, to the views of historian-philosopher Thomas Kuhn, whose influential book was all about sharp scientific revolutions rather than gradual evolution.
Another useful purpose of this anniversary year is that it provides an opportunity to reflect on one of the most important icons and organizing principles in the whole of science, which is unfortunately taken for granted a good deal of the time. The common view that the periodic table is complete, and presents merely a useful tool for looking up atomic weights, could not be further from the truth.
Its central role in chemistry and related fields has been neglected, and there has been a renewed interest among philosophers of chemistry in trying to gather a deeper understanding of its status and real meaning.
The periodic table continues to be extended with the discovery, or rather the artificial synthesis, of new elements. At present, the periodic table appears to be absolutely complete for the first time—and probably the last time—in the foreseeable future. The official recognition of elements 113, 115, 117, and 118 a few years ago has meant that the seventh period in the table has no remaining gaps. But the current completeness is something of an illusion, because there are active efforts to synthesize elements 119 and 120, and once this feat is achieved, a new period of 50 elements will need to be opened up.
Yet another sense in which the periodic table remains a source of lively debate and controversy consists of the recent work to try to settle the membership of group 3 of the periodic table.
Some books show it to be scandium, yttrium, lanthanum, and actinium, whereas others substitute the elements lutetium and lawrencium for lanthanum and actinium.
There are further debates involving the obvious question of whether the synthesis of new elements can continue indefinitely or whether it will end at some point along the axis of increasing atomic number. Given that these elements are increasingly less stable, the second option is almost universally accepted, but not which atomic number will represent the element at the very end of the table. Some argue for 137, whereas other, more detailed calculations point to 172 or perhaps 173.
In addition, there are what might be called threats to the very existence of the periodic table, which makes us question its universality and range of application. Since the second half of the 20th century, relativistic effects have become increasingly recognized as playing an important role in the how atoms and elements behave. Briefly put, as atoms get heavier, the inner electrons adopt speeds that approach that of the speed of light. As a result, a kind of length contraction occurs—or rather, the radii of inner electrons tend to decrease—something that has an effect on other electrons in the atom. Suffice it to say that such effects are strong enough to cause many heavy elements to “misbehave,” in the sense that they do not react in the ways that one might expect them to, according to the groups of the periodic table in which they fall.
A second area in which the periodic table is being pushed to its limits is research in which matter is subjected to enormously high pressures, with the result that, again, atoms and their elements begin to behave in an unexpected manner that would not be predicted from the familiar periodic table.
The November-December, 2019 issue of American Scientist hopes to contribute to the recently awakened interest in the periodic table. Below, find links also to numerous previously published articles on the historical development of the periodic table, reviews of books that have been written about the table, and other articles from the central science of chemistry that inevitably refer to the periodic table as their organizing framework.
- A. Brunning, A Timeline of the Discoveries of Chemical Elements, American Scientist, Vol. 107, No. 3, 136, 2019.
- J. Johnson, A Chemical History of the Universe, American Scientist, Vol. 106, No. 5, 264, 2018.
- E. R. Scerri, Master of Missing Elements, American Scientist, Vol. 102, No. 5, 358, 2014.
- J. James, Imagining the Invisible, American Scientist, Vol. 98, No. 6, 500, 2010 — a book review of Alan J. Rocke's Image and Reality.
- R. Hoffman, The Squeeze is On, American Scientist, Vol. 97, No 2, 108, 2009.
- E.R. Scerri, The Past and Future of the Periodic Table, American Scientist, Vol. 96, No. 1, 52, 2008.
- "Table the Discussion," American Scientist, Vol. 96, No. 3, 179, 2008 — an associated letter to "The Past and Future of the Periodic Table" to which Eric Scerri responds.
- S. Mauskopf, Elemental Deductions, American Scientist, Vol. 95, No. 5, 456, 2007 — a book review of Eric Scerri's The Periodic Table: Its Story and Its Significance.
- T. Royappa, It's Elementary, American Scientist, Vol. 91, No. 3, 272, 2003 — a book review of Philip Ball's The Ingredients: A guided tour of the elements.
- A. Butler, Chemistry's Coming of Age, American Scientist, Vol. 89, No. 5, 473, 2001— a book review of Paul Strathern's Mendeleyev’s dream.
- T. Royappa, Waiting to Take You Away, American Scientist, Vol. 89, No. 3, 278, 2001 —a book review of Arthur Greenberg's A Chemical History Tour.
- E.R. Scerri, The Periodic Table and the Electron, American Scientist, Vol. 85, No. 6, 546, 1997. —other articles that refer to the periodic table as their organizing framework—
- "Super-Heavy Element Confirmed,” American Scientist, Vol. 101, No. 6, 408, 2018 — an item highlighted in the news
- A. Grinthal, W. L. Noorduin, J. Aizenberg, A Constructive Chemical Conversation, American Scientist, Vol.104, No. 4, 228, 2016 — constructing recognizable shapes with chemistry.
- S. Bose, S. F. Robertson, A. Bandyopadhyay, 3D Printing of Bone Implants and Replacements, American Scientist, Vol. 106, No. 2, 112, 2018 — tailoring chemistry and structure of biomaterials
- K. Heng, The Imprecise Search for Extraterrestrial Habitability, American Scientist, Vol. 104, No. 3, 146, 2016 — how what is expected from elements in the same group within the periodic table doesn’t work: Silicon is not a carbon replacement for life
- H. Reich, Names, Simplified, American Scientist, Vol 103, No. 6, 422 2015 — a book review of Randall Monroe's Thing Explainer: Complicated Stuff in Simple Words, a book that includes an explanation of the periodic table
- J. Butterworth, What's Next for Particle Physics?, American Scientist, Vol. 103, No. 2, 144, 2015 —the “spin” for elements
- R. Mortimer, Switching Colors with Electricity, American Scientist, Vol. 101, No. 1, 38, 2013 — elements’ location in the periodic table.
- R. Hoffmann, That's Interesting, American Scientist, Vol. 99, No. 5, 374, 2011 — what is expected from elements in the same group within the periodic table…
- R. F. Hargraves, R. Moir, Liquid Fluoride Thorium Reactors, American Scientist, Vol. 98, No. 4, 304, 2010 —includes reference to elements above uranium in the periodic table
- A. Dzierba, QCD with a Light Touch, American Scientist, Vol. 97, No. 2, 165, 2009 — a book review of Frank Wilczek's The Lightness of Being
- D. S. Silver, Knot Theory's Odd Origins, American Scientist, Vol. 94, No. 2, 158, 2006 — physics as a table of elements
- B. Hayes, Naming Names, American Scientist, Vol. 93, No. 1, 6, 2005 — how tables are read
- J. E. Thomas, M. Gehm, Optically Trapped Fermi Gases, American Scientist, Vol. 92, No. 3, 231, 2004 —how the periodic table "transforms" when elements are chilled to near absolute zero
- S. Scandolo, R. Jeanloz, The Centers of Planets, American Scientist, Vol. 91, No. 6, 516, 2003 — how the periodic table “transforms” when elements are put under high pressure
- S. Kadlecek, Magnetic Resonance Imaging with Polarized Gases, American Scientist, Vol. 90, No. 6, 540, 2002 — one reason why the periodic table's arrangement is helpful
- P. Laszlo, Enthralled by the Elements, American Scientist, Vol. 90, No. 4, 196, 2002 — a book review of Oliver Sacks's Uncle Tungsten: Memories of a Chemical Boyhood
- R. Hoffman, Carbides, American Scientist, Vol. 90. No. 4, 318, 2002
- M. Barsoum, T. El-Raghy, The MAX Phases: Unique New Carbide and Nitride Materials, American Scientist, Vol. 89, No. 4, 334, 2001 — how MAX Phases “fit in” (or don’t) with the periodic table
- P. and P. Morrison, 100 or so Books that shaped a Century of Science, American Scientist, Vol. 87, No. 6, 542, 1999 — includes Primo Levi's The Periodic Table
- R. Hoffmann, Döbereiner's Lighter, American Scientist, Vol. 86, No. 4, 326, 1998 — includes mention of forerunners of Mendeleyev’s periodic table