Today we have the opportunity to toast the periodic table. Why, you ask? It's National Periodic Table Day.
For those whose memories of chemistry classes are vague, a periodic table is a matrix comprising seven rows (periods) and 18 columns (groups). It organizes chemical elements by atomic number horizontally and electron configuration vertically. In so doing we are able to assign like properties to groups, which helps chemists in predicting certain behaviors.
Back in 1869 when the periodic table was created, its inventor, Dmitri Mendeleev, was able to identify gaps that led him to predict 10 elements that hadn't yet been discovered. He was right about eight of them.
The periodic table hangs in science classrooms worldwide. A quick glance helps users in all sorts of ways, from understanding an element's properties to anticipating reactions and identifying new possible elements.
A viewer will notice 94 natural elements making up the core of the table. Two detached rows were added on the bottom for synthesized elements made in laboratories or nuclear reactors. The core table features a column on the left of highly reactive alkali metals, like sodium. On the far right sits a column of noble gases like helium. In between these columns are transition elements, which includes metals and halogens.
For the last 150 years, the periodic table has become a Rosetta Stone of sorts, crossing geographies and languages. It significantly contributes to instituting a rational framework and has been dubbed Chemistry's Most Important Breakthrough (New Scientist magazine).
Consider a few of the breakthroughs this table has enabled by allowing us to advance the field of chemistry.
• Chemical synthesis of Taxol to treat cancer: Taxol is a chemical compound found in Pacific yew trees, which have been over-harvested and are in rare supply. Because of Taxol's therapeutic impact in treating cancer, chemists have engineered a semisynthetic version that's widely used today, earning Taxol blockbuster status.
• Unraveling the details of surface chemistry: Through a molecular understanding of chemical reactions, we can answer simple questions such as "what causes iron to rust?" There are more complex applications: catalytic converters used to clean polluted air, anti-corrosion technology to protect surfaces and engineered biomaterials for medical purposes. All are enabled by our ability to decipher chemical reactions.
• Flat screen displays: By moving from cathode ray tubes to liquid crystal displays, our screens have become less bulky. A molecule known as 5CB helped crack the code to engineer liquid crystal displays that can function at useful temperatures.
The periodic table is an evolving reference guide that will continue to shape our world. When professor Leland Allen added an extra dimension to the table in 1992 that focused on chemical bonding and energy calculations, he signaled a broader era of predictions and quantifications.
For all these reasons and more, let's raise our glass to the periodic table.
Editorial on 02/07/2020