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Tennessine,  117Ts
General properties
Pronunciation/ˈtɛnɪsn/[1] (TEN-ə-seen)
Appearancesemimetallic (predicted)[2]
Mass number294 (most stable isotope)
Tennessine in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Atomic number (Z)117
Groupgroup 17
Periodperiod 7
Element category  unknown chemical properties, but probably a post-transition metal[3][4]
Electron configuration[Rn] 5f14 6d10 7s2 7p5 (predicted)[5]
Electrons per shell
2, 8, 18, 32, 32, 18, 7 (predicted)
Physical properties
Phase at STPunknown phase (predicted)[5][6]
Melting point623–823 K ​(350–550 °C, ​662–1022 °F) (predicted)[5]
Boiling point883 K ​(610 °C, ​1130 °F) (predicted)[5]
Density (near r.t.)7.1–7.3 g/cm3 (extrapolated)[6]
Atomic properties
Oxidation states(−1), (+1), (+3), (+5) (predicted)[2][5]
Ionization energies
  • 1st: 742.9 kJ/mol (predicted)[7]
  • 2nd: 1435.4 kJ/mol (predicted)[7]
  • 3rd: 2161.9 kJ/mol (predicted)[7]
  • (more)
Atomic radiusempirical: 138 pm (predicted)[6]
Covalent radius156–157 pm (extrapolated)[6]
Other properties
Natural occurrencesynthetic
CAS Number54101-14-3
Namingafter Tennessee region
DiscoveryJoint Institute for Nuclear Research, Lawrence Livermore National Laboratory, Vanderbilt University and Oak Ridge National Laboratory (2009)
Main isotopes of tennessine
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
293Ts[8] syn 22 ms α 289Mc
294Ts[9] syn 51 ms α 290Mc
| references

Tennessine (former Ununseptium) is the superheavy man-made chemical element. It has a symbol Ts and atomic number of 117. It is the second heaviest element of all, and is the second to last element. It is in group 17 in the periodic table, where the halogens are. Its properties are not yet fully known. It is probably a metalloid. The discovery of tennessine was announced in 2010 by scientists in Russia and the United States. They collaborated. It is the most recently discovered element as of 2019.

History[change | change source]

Before discovery[change | change source]

In 2004, the Joint Institute for Nuclear Research (JINR) team in Dubna, Moscow Oblast, Russia planned an experiment to synthesize (create) element 117. It is called element 117 because the number of protons in its atom is 117. To do this, they needed to fuse the elements berkelium (element 97) and calcium (element 20). However, the American team at Oak Ridge National Laboratory, the only producer of berkelium in the world, had stopped making berkelium for a while. So, they synthesized the element 118 first using californium (element 98) and calcium.

The Russian team wanted to use berkelium because the isotope of calcium used in the experiment, calcium-48, has 20 protons and 28 neutrons. This is the lightest stable or almost stable nucleus (the middle part of an atom) with much more neutron than proton. Zinc-68 is the second-lightest nucleus of this kind, but it is heavier than calcium-48. Since tennessine has 117 protons, they need another atom with 97 protons to be combined with the calcium atom, and berkelium has 97 protons.

In the experiment, the berkelium is made into a target and the calcium is fired in the form of a beam to the berkelium target. The calcium beam is created in Russia by removing the small amount of calcium-48 from natural calcium using chemical means. The nuclei that is made after the experiment will be heavier and is nearer to the island of stability. This is the idea that some very heavy atoms can be quite stable.

Discovery of Tennessine[change | change source]

The berkelium target used for the synthesis of tennessine, in solution form

In 2008, the American team started again to create berkelium, and they told the Russian team about it. The program made 22 milligrams of berkelium, and this is enough for the experiment. Soon after, the berkelium was cooled in 90 days and was made more pure by chemical means in 90 more days. The berkelium target had to be taken to Russia quickly because the half-life of the isotope of berkelium used, berkelium-249, is only 330 days. In other words, after 330 days, half of all the berkelium will no longer be berkelium. Actually, if the experiment did not start six months after the target was made, it would have been cancelled because they did not have enough berkelium for the experiment. In summer 2009, the target was packed into five lead containers and was sent by a commercial flight from New York to Moscow.

Both teams had to face the bureaucratic obstacle between America and Russia before they send the berkelium target to allow it to arrive in Russia on time. However, there were still problems: Russian customs did not let the berkelium target get into the country twice due to missing or incomplete paperwork. Even though the target went over the Atlantic Ocean five times, the whole journey only took a few days. When the target finally got into Moscow, it was sent to Dimitrovgrad, Ulyanovsk Oblask. Here, the target was placed on a thin titanium film (layer). This film was then sent to Dubna where it was placed inside the JINR particle accelerator. This particle accelerator is the most powerful particle accelerator in the world for the creation of superheavy elements.

The experiment began in June 2009. In January 2010, the scientists at the Flerov Laboratory of Nuclear Reactions announced within the laboratory that they had found the decay of a new element with atomic number 117 through two decay chains. The odd-odd isotope does 6 alpha decays before doing a spontaneous (sudden) fission. The odd-even isotope does 3 alpha decays before fission. On 9 April 2010, an official report was released in the Physical Review Letters journal. It showed that the isotopes that were mentioned in the decay chains were 294Ts and 293Ts. The isotopes were made as follows:

249Bk + 48Ca → 297Ts* → 294Ts + 3 n (1 event)
249Bk + 48Ca → 297Ts* → 293Ts + 4 n (5 events)

References[change | change source]

  1. Ritter, Malcolm (9 June 2016). "Periodic table elements named for Moscow, Japan, Tennessee". Associated Press. Retrieved 19 December 2017.
  2. 2.0 2.1 Fricke, B. (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry 21: 89–144. doi:10.1007/BFb0116498. https://www.researchgate.net/publication/225672062_Superheavy_elements_a_prediction_of_their_chemical_and_physical_properties. Retrieved 4 October 2013. 
  3. Royal Society of Chemistry (2016). "Tennessine". rsc.org. Royal Society of Chemistry. Retrieved 9 November 2016. A highly radioactive metal, of which only a few atoms have ever been made.
  4. GSI (14 December 2015). "Research Program – Highlights". superheavies.de. GSI. Retrieved 9 November 2016. If this trend were followed, element 117 would likely be a rather volatile metal. Fully relativistic calculations agree with this expectation, however, they are in need of experimental confirmation.
  5. 5.0 5.1 5.2 5.3 5.4 5.5 Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN 1-4020-3555-1.
  6. 6.0 6.1 6.2 6.3 Bonchev, D.; Kamenska, V. (1981). "Predicting the Properties of the 113–120 Transactinide Elements". Journal of Physical Chemistry 85 (9): 1177–1186. doi:10.1021/j150609a021. https://www.researchgate.net/publication/239657207_Predicting_the_properties_of_the_113_to_120_transactinide_elements. 
  7. 7.0 7.1 7.2 Chang, Zhiwei; Li, Jiguang; Dong, Chenzhong (2010). "Ionization Potentials, Electron Affinities, Resonance Excitation Energies, Oscillator Strengths, And Ionic Radii of Element Uus (Z = 117) and Astatine". J. Phys. Chem. A 2010 (114): 13388–94. doi:10.1021/jp107411s. 
  8. Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E. et al. (2014). "48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr". Physical Review Letters 112 (17): 172501. doi:10.1103/PhysRevLett.112.172501. PMID 24836239. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.172501. 
  9. Oganessian, Yu. Ts. et al. (2013). "Experimental studies of the 249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope 277Mt". Physical Review C 87 (5): 054621. doi:10.1103/PhysRevC.87.054621. 

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