The foundation of modern chemistry and beyond

The orderly arrangement of the world’s building blocks known as the Periodic Table of Elements that Dimitri Mendeleev created 150 years ago not only launched the modern science of chemistry but also continues to influence some of the most advanced biomedical research.

The rows of 118 chemical elements represent the material making up everything in nature and the physical materials of the technology that drives our world – transportation, medicines, electronic and digital systems, for instance.

Dimitri Mendeleev

Mendeleev, a Russian chemist, created the table in 1869, listing the 63 known elements at the time such as iron (Fe) and oxygen (O) by atomic weight, which is the average weight of the protons and neutrons in an atom of each element. The table catalogs periodicity or recurring patterns among the elements, helping scientists to identify new elements and predict chemical reactions.

“This was the first effort in chemistry that applied systematized knowledge of elements and discovered a level of periodicity that enabled the understanding of chemical elements in a very unique way,” said Alex Tropsha, K.H. Lee Distinguished Professor in Carolina’s Eshelman School of Pharmacy and graduate of the chemistry department at Moscow State University in Russia.

On par with Darwin and Linnaeus

Tropsha, like most other scientists, considers the table’s importance on par with Darwin’s theory of evolution and Linnaeus’ taxonomy for classifying and naming organisms.

“It effectively enabled rational thinking about chemical composition of individual compounds, and that led to rational thinking about how chemical composition and properties of chemical matter are connected,” he said.

Alex Tropsha, K.H. Lee Distinguished Professor in Carolina’s Eshelman School of Pharmacy

The table’s importance led the United Nations to designate 2019 as the International Year of the Periodic Table of the Elements — commemorating the system’s 150^th anniversary.

And, the table is still influencing important scientific thinking. Tropsha points to the creation of the NIH’s Biomedical Data Translator (BDT) project in 2016. The BDT connects 200 scientists in the U.S. such as Tropsha who integrate multiple data sources in hopes of developing insights to guide clinical care, inform clinical and translational research, stimulate drug discovery, influence public-health decisions and help find new treatments and faster cures for disease. BDT creator Chris Austin, the director of the NIH’s National Center for Advancing Translational Sciences described BDT’s work as a modern-day effort to systematize biomedical knowledge. That work parallels the table’s function, Tropsha said.

“Here we are in 2019 and the periodic table is still influencing the very highest level of philosophy behind the most modern and perhaps most comprehensive and biomedical science project ongoing now,” Tropsha said.

Worldwide and local recognition

The worldwide recognition of the table’s importance included the Russian-American Scientists Association’s 2019 conference in Chapel Hill, which featured a session named in honor of Mendeleev that Tropsha moderated. Alexander “Sasha” Kabanov, association president and conference organizer, is the Mescal S. Ferguson Distinguished Professor and director of the Center for Nanotechnology in Drug Delivery at the UNC Eshelman School of Pharmacy and co-director of the Carolina Institute for Nanomedicine.

The session featured several speakers, including an “entertaining and scientifically accurate” talk that dispelled the myth that Mendeleev invented vodka, Tropsha said.

Elsewhere on campus, a tangible, long-lasting salute to Mendeleev’s Table hangs in Kenan Science Library. A work of art and information, the 5 x 8 foot “Periodic Table of the Elements Project (2019) mixed media on wood” contains 118 tiles representing each element. Students, faculty, staff and community members created the tiles to artistically represent each element’s name, discovery, physical properties, chemical family and uses. The colorful tiles, ranging from literal to whimsical, include everything from scientist portraits to a piece of toast to a moving toy shark.

Danianne Mizzy, former university librarian, conceived of the project about five years ago. Glenn Walters, research associate professor, oversaw the production of the maple-laminate plywood base into which people slid their artsy tiles. D. J. Fedor, Hanes Makerspace manager and technical manager, did the majority of the fabrication.

Similar to the way the large wooden board reminds people of the table’s significance, Tropsha said that the table is always in the back of his mind. He refers to it every time he teaches a course on computer-aided drug discovery.

“I reference the table in the context of the overarching problem of understanding the linkage between chemical composition and property, which is why we synthesize chemical matter,” Tropsha said. “We can use the existing substance to forecast or infer properties of unknown chemical substances from their composition. Prior to Mendeleev’s invention, chemistry was completely empirical, not this whole process of rational thinking it became.”

The Periodic Table of the Elements board hanging in Kenan Science Library contains tiles created by dozens of faculty, staff and students. Designs range from the literal to the whimsical. (Photo courtesy of the College of Arts & Sciences)