The periodic table remains essential after 150 years

It’s another raw day in St. Petersburg, Russia, but the man striding down the University Embankment along the Neva River isn’t pondering how the icy wind off the Gulf of Finland chills his bones or whether Emperor Alexander II’s reforms will increase salaries for professors like him. Instead, Dmitrii Mendeleev is imagining how he could reveal the chemical underpinnings of the universe on a single page.

This year marks the 150th anniversary of Mendeleev’s invention of the periodic table of the elements in 1869, which not only foretold an internal structure to the atom and the existence of elements not yet discovered, but also hinted at the profundities of quantum mechanics.
I’ve walked those windswept streets by the university in St. Petersburg, and I like to imagine Mendeleev, who appears to have been the archetype of the brilliant, disheveled professor, walking deep in thought while the carriages of aristocrats clattered by on their way to the Winter Palace. But my own knowledge of how Mendeleev came to create this road map of element characteristics and relationships doesn’t extend much beyond daydreaming while staring at the chart in high school science classes.

Fortunately, Science News contributor and former editor in chief Tom Siegfried is deeply familiar with the history of Mendeleev’s discovery and its impact. His essay chronicles the decades of effort by scientists in the 19th century to figure out the relationships among the elements, and how Mendeleev, while writing a textbook on inorganic chemistry, managed to crack the code.

Siegfried is clearly the right person to open our 2019 coverage of the periodic table’s notable birthday.

“I was a chemistry major in undergrad,” Siegfried told me. “I wrote papers about the history of the periodic table.” When he was a college student, the table ended at element 103, lawrencium. Now it’s filled in all the way to No. 118, the heavyweight oganesson, one of the four synthetic elements officially named in late 2016 (SN: 1/21/17, p. 16). “That was fun to watch happen,” Siegfried says. And he’s looking forward to more fun in the future; the story of the periodic table isn’t over. “It’s ongoing, as new elements and new aspects of atoms are discovered,” he says.
So the story of the periodic table hasn’t ended — and our coverage of the 150th anniversary is just beginning. By now you might have surmised that we here at Science News are major fans of the periodic table, and the scientists and science behind it. We’ve even included the current version of the table in this issue, embellished with surprising points of interest by special projects editor Elizabeth Quill.

Do you have a favorite element fact or memory of the periodic table? If so, please let us know by e-mailing us at editors@sciencenews.org or on Twitter @ScienceNews. We’ll be sharing selected bits throughout the year.

Stay tuned for more stories in the magazine and on www.sciencenews.org as we celebrate this very big birthday together.