Despite all the problems and tumult in the world, the progress of science marches on. According to this article in Yahoo News, the International Union of Pure and Applied Chemistry has officially added four recently discovered elements to the periodic table.
Four new elements have been permanently added to the periodic table, after their discoveries were verified by the global chemistry organization that oversees the table. The International Union of Pure and Applied Chemistry (IUPAC) last week announced that elements 113, 115, 117, and 118 have met its criteria for discovery, making them the first elements to be added to the periodic table since 2011. Their addition also completes the seventh row of the periodic table.
All four man-made elements currently have placeholder names, and will be officially named over the next few months. Elements 115, 117, and 118 were discovered by a team of scientists from the Joint Institute for Nuclear Research in Dubna, Russia and Lawrence Livermore National Laboratory in California. The Russian-American team had also claimed discovery of element 113, currently known as ununtrium, but IUPAC credited a team from the Riken institute in Japan. Element 113 will therefore be the first element to be named by researchers in Asia.
“Greater value than an Olympic gold medal.”
Discovering superheavy elements has proven difficult because they rapidly decay. But research has revealed slightly longer lifetimes for more recent superheavy elements, raising hopes that scientists may eventually discover the so-called “island of stability” — a group of elements that are both superheavy and stable. Kosuke Morita, who led research on element 113 at Riken, said in a statement that his team will now “look to the uncharted territory of element 119 and beyond.”
“To scientists, this is of greater value than an Olympic gold medal,” Ryoji Noyori, the former president of Riken and Nobel laureate in chemistry, tells The Guardian.
As the article states, the IUPAC gives temporary, or placeholder, names to newly discovered elements until there is some consensus on the official names. This naming can be contentious if more than one team makes a credible claim to be the discoverer of the element. The placeholder name is simply the atomic number of elements expressed in Latin or Greek with “-ium” added. Thus, element 113 is ununtrium. Elements 115, 117, and 118 are ununpentium, ununseptium and ununoctium.
These elements are spoken of as being discovered, but it would be more accurate to say that they have been created or synthesized since no element with an atomic number higher than 92, uranium, is found in nature. Elements with higher atomic numbers are radioactive with half-lives too short to have survived since the creation of the Earth and solar system. Every element has unstable, or radioactive, isotopes but every element with an atomic number up to 82, lead, with the exception of technetium, atomic number 43, has at least one staple isotope. I am not sure if scientists know precisely why some isotopes of some elements are stable while others are unstable, but it seems to have something to do with the proportions of protons and neutrons in an atomic nucleus. Thus carbon-12 with 6 protons and 6 neutrons is stable while carbon-14 with 6 protons and 8 neutrons is radioactive. Uranium-238 with 92 protons and 146 neutrons is weakly radioactive with a half-life of over four billion years, but uranium-234 with 92 protons and 142 neutrons is slightly more radioactive with a half-life of 246,000 years.
For elements with atomic numbers higher than uranium’s, there is a tendency to be more radioactive with shorter half-lives. Americium with an atomic number of 95 has a half-life of around 7370 years. Fermium with atomic number 100 has a half-life of 100 days. Dubnium, atomic number 105, has a half-life of about 28 hours. Elements with higher atomic numbers have half-lives measured in hours, minutes, or seconds. The most stable isotopes of the four new elements, 113, 115, 117, and 118 have half-lives of 20 seconds, 220 milliseconds, 51 milliseconds, and .89 milliseconds, respectively. Strangely, this decline in the length of the half-life does not seem to be as great as expected and it is hoped that at some point there will be the Island of Stability mentioned in the article, where larger atomic nuclei will have the right configuration of protons and neutrons to permit some degree of stability, though whether such atoms will last for seconds, days or years is unknown. Since the processes by which these super heavy elements are created generally only makes a few atoms at a time and these decay quickly the hope is that the elements in the island of stability will be stable enough to permit some research into the chemical and physical properties of super heavy elements.
I don’t suppose there is much practical use for these discoveries, though you never know, but it is a refreshing change to read about people who are adding to humanity’s store of knowledge about the world as opposed to those intent on tearing everything down.
- Element 115, in Moscow’s name? (in.rbth.com)