Hanging on the wall in my office I still have my very first periodic table. It was given to me in the late seventies by my high school chemistry teacher, Mrs. Clarke. It’s woefully out of date but it has great sentimental value.
There are 103 named elements on my old periodic table. Elements 93-103, the transuranic elements (a.k.a. elements higher than uranium, #92) had all been discovered and were named on the periodic table. Elements 104-106 had been discovered before I took high school chemistry, although they would not be named until 1997.
I remember my high school chemistry teacher telling us that scientists would discover heavier and heavier elements until, one day, element #112 would be synthesized. She told us that the synthesis of element #112 would complete what is known as a d-shell of electrons and, with the fully completed shell, the new atom might have interesting properties and be more stable than other transuranic elements. Element #112 WAS discovered in February of 1996 by a team of German researchers at the GSI Helmholtz Center for Heavy Ion Research. The German team created Element #112 by firing accelerated zinc-70 nuclei (atomic mass = 30) at a target made of lead-208 nuclei (atomic mass = 82) in a heavy ion accelerator. 82 + 30 = 112 and hence element #112 was born. So why have I thought of element #112 recently? Because it was just named this past month! The name? Copernicium. The element was named after Nicolaus Copernicus (1473 – 1543), the first astronomer to formulate a comprehensive heliocentric theory of the universe. The International Union of Pure and Applied Chemistry (IUPAC) will officially endorse the element’s name in about six months. So, thirteen years after it was discovered, element #112 has had its existence independently verified and been given a name. Why did it take thirteen years?
The experiment that created it is very hard to duplicate and so, to date, only about 75 atoms of the material have ever been synthesized and characterized. It is fun to speculate what properties it would have if enough were made at one time. It sits right below mercury on the periodic table so maybe it too would be a shiny, metallic liquid. Whatever its macroscopic properties would be, its name is copernicium and it completes the 4th d-shell of electrons in the periodic table. To me, that’s exciting! Elements 113-118 have been discovered and await confirmation and naming. They complete the 6th p-shell of electrons on the periodic table. Will element #119 be discovered soon and when it is, by whom? I’ll be keeping track, but I will still never throw out my old, beat up periodic table from my high school days.