Stories of the Periodic Table: A Review of The Disappearing Spoon

Sam Kean's The Disappearing Spoon and Other True Tales of Madness, Love, and the History of the World from the Periodic Table of Elements (2011) captures the wonder and power of the periodic table through myriad stories of the elements themselves, as well as stories of the scientists and others whose lives intersected with them.

When I studied it in a college chemistry class, I was fascinated by how the arrangement of the periodic table captured the essence of the different elements and predicted their relationships to each other.

(The version of the table presented above was downloaded from the Los Alamos National Laboratory website.  As the product of a government agency (which I hope will continue to exist), I assume it is in the public domain.)

Kean, a widely published science writer, provides enough science for the reader to gain an appreciation of the basis upon which the table functions, though, to some extent, in his hands, that's secondary to the adventures and misadventures of the people he describes.  It's the latter that moves the book along.  He writes

[T]here's a funny, or odd, or chilling tale attached to every element on the periodic table.  At the same time, the table is one of the great intellectual accomplishments of humankind.  It's both a scientific accomplishment and a storybook . . . .  (p. 7)

As Kean notes, an element is "a substance that cannot be broken down or altered by normal, chemical means."  (p. 15)  Further division destroys it.  One simile he uses for the periodic table is a castle.  The overall shape does hint at castle turrets and walls.  Critical to that analogy is that each brick in the structure, representing a discrete element, is crucial to the table, moving or removing any one of them brings down the structure, putting a line to the arrangement.  The other simile Kean employs is that of a map.  Where an element falls on that map "determine[s] nearly everything scientifically interesting about it.  For each element, its geography is its destiny."  (p. 13)  How that map is read is critical.  He stresses that horizontal relationships in the table are perhaps less significant than vertical ones because reading up and down the columns "reveals a rich subtext of relationships among elements, including unexpected rivalries and antagonisms.  (p. 31)

Key to the entire table is the number and arrangements of electrons in each element.  They are located at different energy levels in the atom, and, beyond the two needed to fill the innermost level, each atom will beg, borrow, or steal enough electrons from other atoms to populate its uppermost level with an appropriate number, usually eight.  Kean stresses that the "octet rule" does explain a great deal of the behavior of atoms, particularly how they combine with other atoms.  Elements are placed in the table according to their atomic number, that is, the number of protons in the nucleus, which, in a neutral atom, is also the number of electrons in the atom.

Kean captures the importance of this when he discusses the different bonding behavior of carbon and oxygen.  Oxygen, element number 8, has 8 electrons and, given that 2 of them are in the lowest energy level, the higher has 6.  This means oxygen is impelled to garner two additional electrons (the octet rule) which, he notes, isn't too difficult a task, meaning oxygen can be choosey about which elements it bonds with.  In contrast, carbon at number 6 has 4 electrons in its highest energy level and needs to find another 4 to satisfy the octet rule.  "That's harder to do, and the upshot is that carbon has really low standards for forming bonds.  It latches onto virtually anything."  (p. 35)  This helps explain why life on Earth is carbon-based.  Carbon, ever in search of electrons, bonds into complex chains of atoms and constitutes "the backbone of amino acids, which string together like beads to form proteins."  (p. 34)

Each chapter of the book is organized around a cluster of elements because each cluster provides fertile ground for a linked set of stories, not necessarily because the elements in a group are reflective of relationships shown in the table.  A few of the element groups he creates are:  medicinal elements, elements that have been caught up in "pathological science" (think cold fusion), elements explored at extremely low temperatures, elements with a strong financial facet, elements discovered as part of cold war politics, and elements that in direct or subtle ways poison human beings.  (A minor quibble:  Kean would have done the lay reader a favor by defining each chemical symbol used at the beginning of each chapter.)

The stories in each chapter of the elements and the people somehow linked to them serve to capture science being done methodically and carefully with beautiful results, or science replete with errors or happenstance.  Lives are bathed in glory or disappointment, honors are won and also lost.  Indeed, in these stories, lives may be lost.  It's an amazing panoply of human emotion and action.

Representative of the way Kean approaches his subjects is his description of the source of the book's title.  In the chapter he titles The Galapagos of the Periodic Table, Kean tells stories involving the elements arsenic, gallium, cerium, yttrium, yttrium, erbium, and terbium.  The chapter title highlights the importance of the Swedish hamlet of Ytterby on the island of Resaro to the periodic table.  In Kean's telling, Ytterby is as central to the periodic table as were the Galapagos to the theory of evolution through natural selection put forward by Charles Darwin (1809-1882).  (I will return to this comparison of the periodic table to the theory of natural selection later.)  The last four elements grouped in this chapter are rare-earth elements, all discovered in a mine at Ytterby (as were three others not in this chapter grouping).  Yes, Kean recounts why Ytterby was so rich in these rare-earth elements and how they were discovered, but it's gallium (unrelated to Ytterby) that, to my mind, occupies center stage in this chapter, though it's but one small part of a very busy chapter.  Gallium, element 31, was among the elements whose existence was predicted by Dimitri Mendeleev (1834-1907), the so-called father of the periodic table, using the table he'd constructed.  Later, when a Frenchman, Lecog de Boisbaudran (1838-1912), claimed to have discovered this metal, a debate ensured over who should have credit.  It's unclear from Kean's account who really prevailed in the tussle, though the element has kept the name Lecoq de Boisbaudran assigned it.  It's the predictive power of the Mendeleev's periodic table that's the big take-away from this chapter for me.  But Kean balances that aspect of the gallium story with a bit of humor.  Remarkably, gallium at normal room temperature is a solid, but it turns to liquid at 84 degrees Fahrenheit or higher.  Further, it's one of the rare liquid metals that can be safely touched with a bare hand.  He  writes:

As a result, gallium has been a staple of practical jokes among the chemistry cognoscenti ever since . . . .  One popular trick, since gallium molds easily and looks like aluminum, is to fashion gallium spoons, serve them with tea, and watch as your guests recoil when their Earl Grey "eats" their utensils.  (p.54)

Hence, the "disappearing spoon."

Though I thoroughly enjoyed the book and learned much from it, I dissent from Kean on one important point.  When he discusses Mendeleev's work on constructing his periodic table (Mendeleev didn't create just one, but, over time, many variations, and many more have been designed subsequently), he makes the following assertion:

Overall, Mendeleev's work is comparable to that of Darwin in evolution and Einstein in relativity.  None of those men did all of the work, but they did the most work, and they did it more elegantly than others.  They saw how far the consequences extended, and they backed up their findings with reams of evidence.  (p. 53)

What troubles me about that statement is that I believe that what Mendeleev fashioned, better than anyone had before him, was a table providing a visual display of the elements, capturing the periodicity of characteristics of the elements and depicting very real relationships among them.  There is no denying the power of the table and impact it had on chemistry.  But, as I read Kean, Mendeleev did not understand why the table worked as it did.  Indeed, his organizing principle was not the atomic number of each element (its number of protons), but rather its weight.  For instance, Kean writes

Most of the elements line up on the table in a cattle call of increasing weight.  According to that criterion, nickel should precede cobalt.  Yet to make the elements fit properly - so cobalt sat above cobalt-like elements and nickel above nickel-like elements - chemists had to switch their spots.  No one knew why this was necessary, and it was just one of several annoying cases.  To get around the problem scientists invented the atomic number a a placeholder which underscored that no one knew what the atomic number actually meant.  (p. 99-100)

It took Henry Moseley (1887-1915), in the early 1900s, to discern the basis for the atomic number by firing electron beams at elemental atoms.  He determined that the wave lengths of the emitted X-rays reflected the number of protons in the atom's nucleus.  Thus, he "linked an element's place on the table to a physical characteristic, equating the positive nuclear charge with the atomic number."  (p. 100)

Given the lack of a fundamental understanding of why the periodic table worked as it did when it was initially put forward, I am hesitant to give it equal weight to Darwin's theory of evolution through natural selection.  The periodic law that undergirds the table describes what the reality is for the elements; Darwin's theory of evolution explains why living organisms come in the diversity they do.  I think it's apples and oranges, though I will admit a bias in favor of explanation.