What is Tennessine?
Tennessine is a synthetic chemical element with the symbol Ts and atomic number 117. It is the second-heaviest known element and the penultimate element of the 7th period of the periodic table.
Tennessine is a radioactive, artificially produced element about which little is known. It is expected to be a solid, but its classification is unknown. It is a member of the halogen group.
The element, No. 117 on the Periodic Table of Elements, had previously been designated ununseptium, a placeholder name that means one-one-seven in Latin. In November 2016, the International Union of Pure and Applied Chemistry (IUPAC) approved the name tennessine for element 117.
The IUPAC also approved names for elements 113 (nihonium, with atomic symbol Nh), 115 (moscovium, Mc) and 118 (oganesson, Og).
Tennessine may be located in the “island of stability”, a concept that explains why some superheavy elements are more stable compared to an overall trend of decreasing stability for elements beyond bismuth on the periodic table.
The synthesized tennessine atoms have lasted tens and hundreds of milliseconds. In the periodic table, tennessine is expected to be a member of group 17, all other members of which are halogens.[b] Some of its properties may differ significantly from those of the halogens due to relativistic effects.
As a result, tennessine is expected to be a volatile metal that neither forms anions nor achieves high oxidation states. A few key properties, such as its melting and boiling points and its first ionization energy, are nevertheless expected to follow the periodic trends of the halogens.
Discovery
In 2010 Russian and American scientists announced the production of six atoms of tennessine, which were formed when 22 milligrams of berkelium-249 were bombarded with atoms of calcium-48, at the cyclotron at the Joint Institute for Nuclear Research in Dubna, Russia.
These atoms were of atomic weights 293 and 294. The five atoms with atomic weight 293 decayed into atoms of roentgenium, and that with a weight of 294 decayed into an atom of dubnium. During these decays, they also formed atoms of atomic number 115, or moscovium, which was the first time that element was formed.
Its chemical properties may be similar to those of astatine. In January 2016 the discovery of element 117 was recognized by the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP).
The discoverers named it tennessine after the state of Tennessee, where centres of research into transuranium elements (such as Oak Ridge National Laboratory, the University of Tennessee at Knoxville, and Vanderbilt University) are located. The name tennessine was approved by IUPAC in November 2016.
Just the facts – Element 117 Atomic Data
- Element Name/Symbol: Tennessine (Ts), was formerly Ununseptium (Uus) from the IUPAC nomenclature or eka-astatine from the Mendeleev nomenclature
- Name Origin: Tennessee, the site of Oak Ridge National Laboratory
- Discovery: Joint Institute for Nuclear Research (Dubna, Russia), Oak Ridge National Laboratory (Tennessee, USA), Lawrence Livermore National Laboratory (California, USA) and other US institutions in 2010
- Atomic Number: 117
- Atomic Weight: [294]
- Electron Configuration: predicted to be [Rn] 5f14 6d10 7s2 7p5
- Element Group: p-block of group 17
- Element Period: period 7
- Phase: predicted to be solid at room temperature
- Melting Point: 623–823 K (350–550 °C, 662–1022 °F) (predicted)
- Boiling Point: 883 K (610 °C, 1130 °F) (predicted)
- Density: predicted to be 7.1–7.3 g/cm3
- Oxidation States: The predicted oxidation states are -1, +1, +3, and +5, with the most stable states being +1 and +3 (not -1, like other halogens)
- Ionization Energy: The first ionization energy is predicted to be 742.9 kJ/mol
- Atomic Radius: 138 pm
- Covalent Radius: extrapolated to be 156-157 pm
- Isotopes: The two most stable isotopes of tennessine are Ts-294, with a half-life of about 51 milliseconds, and Ts-293, with a half-life around 22 milliseconds.
- Uses of Element 117: At present, ununseptium and the other superheavy elements are only used for research into their properties and to form other superheavy nuclei.
- Toxicity: Due to its radioactivity, element 117 presents a health risk.
Properties of Tennessine
Tennessine has two isotopes with known half-lives and two with unknown half-lives. The most stable isotope is 294Ts, with a half-life of about 80 milliseconds. It decays through alpha decay. Tennessine’s other isotopes are suspected to decay through both alpha decay and spontaneous fission.
The atomic weight for manmade transuranium elements is based on the longest-lived isotope. These atomic weights should be considered provisional since a new isotope with a longer half-life could be produced in the future.
Uses of Tennessine
At present, tennessine is only used for research. Scientists are investigating the properties of the element and using it to produce atoms of other elements through its decay scheme. There is no known or expected biological role of element 117. It’s expected to be toxic, primarily because of its radioactive and very heavy.