Single White metal seeks dangerous pungent gas

By Cara Feinberg on April 2, 2012 

Theodore Gray's mad scientist lair sits hidden amidst miles of cornfields outside the small college town of Champaign, Illinois. If you drive by too quickly, you'll miss the entrance, an unmarked gravel driveway off an unnamed country road. Turn in, and where you'd expect to see a quaint farmhouse at the end of the driveway, you'll find an industrial-size hangar filled with a 10-year-old-boy's fantasy toys: model rocket kits, mechanical gizmos, rusting antique farm machinery, and jars marked with skulls and crossbones.

The Lair, as Theo calls it, was one of the last stops on our three-month NOVA film shoot for "Hunting the Elements," a two-hour special about chemistry's famous periodic table. Our
crew had been crisscrossing the country and had even traveled to
Russia, and we'd dropped our host, New York Times technology columnist David Pogue, into some of the most dramatic scenarios we could find: a tank of sharks that would (hopefully) be repelled by rare earth metals; a firework testing range, where explosions colored by strontium, copper, and barium were launched amidst a pelting Nor'easter; a desolate stretch of the New Mexico desert, where we blew up a Cadillac Deville with 300 pounds of ammonium nitrate and fuel oil.

Each of these places revealed details about specific elements, but few of them told us much about the periodic table itself, and this is why we headed to the Illinois flatlands to see Theo Gray. Co-founder of Wolfram Research and author of the gorgeous photographic book The Elements, Theo is quite simply a world-class connoisseur of the elements, and he has the collection- -2,379 elemental samples--to prove it.

Until I met Theo, the periodic table was pretty much a mystery--a series of letters and numbers that I recognized, but didn't much understand. My last encounter with the chart, like most people's, was in high school chemistry. But, as it turns out, the chart itself isn't actually that complicated--it was just that I was approaching it wrong. The trick, Theo explained, was to stop thinking like a chemist, and to start a matchmaker. On the far right of the chart were the noble gasses, confirmed bachelors that don't mix with the riff-raff. On the far left, the alkali metals, desperate lonely hearts that react with nearly every element that comes along. In between were the metals, elements that sometimes react, and sometimes don't. And this genius chart that has persisted without challenge for more than a century is the predictive key, pinpointing which pairs will last, and which will go bust.
It's not easy to make a television show about a list of elements, especially one that most people recognize but don't know how to read. Even more daunting, the periodic table doesn't just catalog the elements. It describes their atoms, and the squares around their names are arranged from left to right by the increasing number of protons inside their atoms' nuclei. That alone is more chemistry than most non-chemists want to think about.

But this is where Theo Gray comes in. To understand the chart, he explained, you don't have to know a thing about atoms. A case in point: Dmitri Mendeleev, the 19th-century Russian scientist who created the periodic table, invented it before the structure of atoms was even discovered. He knew the elements' physical characteristics and how they behaved chemically when they came into contact with each other, but he knew nothing about protons, neutrons, and electrons. This, Theo explained, is the key to decoding the periodic table--and Mendeleev's stroke of genius. Without knowing any of the physics to explain the phenomenon, Mendeleev realized it was the elements' behavior--and their reactivity to each other--that should determine the chart's organization. And there has never been a experiment in the century since he designed the chart that has proven him wrong.

To see what he was talking about, Theo told us, we'd have to step into his Lair where he'd set up a makeshift lab bench. Above it, he had hung a net of popcorn and when we tasted it (which we did), it was clear it was in need of a certain seasoning. To improve the taste, however, we'd all have to suit up in protective eyewear, and David Pogue, Theo's designated on-camera assistant, would have to be encased in a flame-retardant shirt and gloves. The experiment, Theo explained, involved two of the most reactive elements on the periodic table: chlorine gas, which can liquefy your insides, and sodium metal, which explodes on contact with water.

What we had were two "desperate Lonely Hearts," Theo explained--two unstable elements that would readily react with each other. Lonely Heart Number One, sodium, came from the table's far left-hand column of the alkali metals, while Lonely Heart Number Two, chlorine, lived on the other side of the table in the halogen column, just left of the noble gasses. Alone, these elements were poisons, but when Theo allowed heated chlorine gas to come into contact with a chunk of sodium metal, a cloud of sodium chloride-- salt--wafted up into the bag of popcorn.


o how does salting up popcorn explain the structure of the periodic table? The simple answer: elements with similar chemical properties live in columns, or families, on the table, and each element in the family reacts in a similar fashion. Some families are full of giving elements, others contain desperate ones looking for handouts, and some are aloof and disconnected from their neighbors, content to fly solo.

Today we have a deeper understanding of how the particles that make up atoms conspire to produce these reactions, but Mendeleev himself didn't know any of this when he designed the table.

After visiting Theo's lair, the periodic table suddenly made sense. The chart I'd thought was just a list of individual elements is actually about their reactivity--the chemistry among elements. There is a reason we use that word to describe our human attractions--some relationships make it, and others combust. If only we humans had a table of our own to tell us which ones were which.

"Hunting the Elements" premieres Wednesday, April 4 at 9 p.m. ET on most PBS stations. Please check your local listings to confirm when it will air near you.