A Flicker of Something Deeper
Periodic Table of Cupcakes. Image courtesy Rosie Cook.
The periodic table is one thing (perhaps the only thing) everyone remembers from high-school chemistry class—though not always fondly. As with that other teenage bugbear, mathematics, the periodic table involves a headachingly intense compression of information, and the way some people could unpack that information with such nerdy nonchalance frustrated some of us to no end. But that density of information is also the table’s great power as a communication tool. Because once it does click, once it does cohere, you can suddenly predict—at a glance—how two elements will react with each other and in what ratios they’ll combine. In mere seconds you can predict the properties of elements you’ve never heard of or that don’t even exist. It’s like those ophthalmology tests for color-blind people: a bold red figure stands out amid what had looked like nothing but grey dots before. It’s a wondrous moment.
The periodic table conveys deeper layers of scientific information as well. Atomic physics governs the unseeably small, while chemistry holds sway over the world of everyday substances, and the two disciplines cross over and intersect on the table. That’s because the chemical properties of atoms arise directly from how their subatomic parts interact. Elements are different from one another because they have different numbers of protons in their nuclei, and their reactive properties are determined by the way their electrons pair up and flit about inside atoms. If electrons and protons had different fundamental properties—if more or fewer could fit in an atomic shell, for instance—we’d have different noble gases, more or fewer transition metals, and so on. The shape and periodicity of the table therefore reflect basic laws of the universe.
And because there’s so much order and regularity in the table, the rare deviation reveals a flicker of even more profound science. Take gold and mercury. In both elements the outermost electrons move so swiftly (approaching the speed of light) that Einstein’s relativity comes into play, saddling the electrons with extra weight and warping their orbits around the nucleus. This characteristic hinders these elements in some ways but also endows them with their most alluring qualities. Most metals form solids because their atoms share electrons readily and form tight bonds. In mercury the electrons that would get shared are the very ones relativity weighs down the most. This quality inhibits sharing, which weakens interatomic bonds—and makes quicksilver liquid. As for gold, changing the electron orbits affects how easily the electrons can jump between orbits and thereby affects the absorption and production of light when they do jump. And it just so happens that the distorted jumps inside a gold atom produce light we see as a rich yellow. Scientists have been trying and failing for a century to unite Einstein’s relativity with quantum mechanics to produce a grander, unified “theory of everything.” Gold and mercury are rare cases where the two fields have united, and beautifully so.
Beyond its science the periodic table reveals things about the scientists who constructed it and discovered its 118 elements. The names of many elements come from Greek and Latin words, a relic of the days when most scientists were noblemen, people educated in classical languages as a matter of course. (That upbringing also explains the many elements named for mythological tales, like tantalum and niobium.) What’s more, the tally of elements named after cities and countries skews heavily toward Europe, a reflection of the European dominance of science in the 18th, 19th, and early 20th centuries. Even the current trend of naming new ultraheavy elements after great scientists (like Lise Meitner’s meitnerium, 109, or Nicolaus Copernicus’s copernicium, 112) reveals more than you might expect. For better or worse, Western cultures tend to venerate individual geniuses, and while you can’t quite say the periodic table has succumbed to our modern celebrity culture, even something as seemingly timeless as the table cannot escape the fashions of its time.
The periodic table says something about human nature too. The discovery of new elements nowadays differs from the discovery of elements in the olden days because scientists aren’t going out into nature and getting their fingernails dirty: they’re actually creating new elements in labs, by smashing beams of particles together and hoping they stick. Admittedly, most of these elements have no practical purpose, which distresses some people: I get asked all the time what these elements are “good for” or whether it’s “cheating” to include them on the table. Based on the fact that they have a unique number of protons, they are indeed bona-fide elements. And however fleeting—most decay in just seconds or even less—these elements do help scientists confirm and refine atomic and nuclear theories. Just as important, though, the creation of artificial elements helps satisfy our incorrigible desire to push beyond nature’s boundaries. Nature gave us 92 elements, but during the past 70 years we’ve added 26 more, with others in the works.
That said, while the novelty of exploration thrills us, as soon as we’ve discovered an exotic new species of element, it goes right into its place—because more than anything else the periodic table reflects our rage for order against the chaos of the world. Its rectilinear shape, so tidy, makes it seem like we have control over the elements: each element has its spot, and each element’s spot defines its properties. And unlike the taxonomies of particle physics or biology, there are no holes, no gaps, no missing links. Everything that can and does exist in our world is a permutation of these 118 elements. Everything. No matter what other information our periodic table conveys, its very existence shouts that startling fact and the even more startling fact that human beings discovered it.
Sam Kean is the author of The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements.