Periodic Table Lab
117Ts[294]

Atomic number 117 · Halogen

Tennessine Ts

Tennessine, discovered in 2010, is the most recently discovered element. Named after the US state of Tennessee, it sits at the bottom of group 17, the halogens. It was the product of international collaboration and would have been impossible without a rare berkelium target made at Oak Ridge, Tennessee.

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Key properties

Atomic number117
Atomic weight[294] (No stable isotope; mass number of a representative isotope in brackets)
CategoryHalogen
Group17
Period7
Blockp
State (25 °C, 1 atm)Solid (Predicted)
Melting point—
Boiling point—
Density—
Electronegativity (Pauling)—
Atomic radius (van der Waals)—
First ionization energy—
Electron affinity—
Oxidation states+5, +3, +1, -1
Discovered2010

Electron configuration

Condensed
[Rn]7s2 7p5 5f14 6d10
Full
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d10 7s2 7p5
Electrons per shell
2 · 8 · 18 · 32 · 32 · 18 · 7

Orbital diagram

1s2↑↓
2s2↑↓
2p6↑↓↑↓↑↓
3s2↑↓
3p6↑↓↑↓↑↓
3d10↑↓↑↓↑↓↑↓↑↓
4s2↑↓
4p6↑↓↑↓↑↓
4d10↑↓↑↓↑↓↑↓↑↓
4f14↑↓↑↓↑↓↑↓↑↓↑↓↑↓
5s2↑↓
5p6↑↓↑↓↑↓
5d10↑↓↑↓↑↓↑↓↑↓
5f14↑↓↑↓↑↓↑↓↑↓↑↓↑↓
6s2↑↓
6p6↑↓↑↓↑↓
6d10↑↓↑↓↑↓↑↓↑↓
7s2↑↓
7p5↑↓↑↓↑

Electron configurations of some superheavy elements (beyond 103) are theoretical predictions.

Position in the table

HHeLiBeBCNOFNeNaMgAlSiPSClArKCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXeCsBaLaCePrNdPmSmEuGdTbDyHoErTmYbLuHfTaWReOsIrPtAuHgTlPbBiPoAtRnFrRaAcThPaUNpPuAmCmBkCfEsFmMdNoLrRfDbSgBhHsMtDsRgCnNhFlMcLvTsOg57–7189–103

Discovery

Making element 117 required a berkelium-249 target to pair with a calcium-48 beam. In 2008–2009 Oak Ridge National Laboratory irradiated material in its High Flux Isotope Reactor for about 250 days and chemically processed it to obtain roughly 22 milligrams of berkelium-249. Because berkelium-249 has a half-life of about 330 days, the target was rushed to Dubna in Russia.

From July 2009 the Joint Institute for Nuclear Research bombarded it with calcium-48, detecting six atoms of tennessine-293 and tennessine-294, announced in April 2010. Oak Ridge, Vanderbilt University, the University of Tennessee and Lawrence Livermore were among the partners. IUPAC recognised the discovery in December 2015, and the name was approved on 28 November 2016.

Origin of the name

The element is named after Tennessee, home of Oak Ridge National Laboratory, Vanderbilt University and the University of Tennessee. Following the tradition of the halogens (fluorine, chlorine, bromine, iodine, astatine), it takes the ending -ine. The symbol is Ts.

Main uses

  • Basic research: It has no uses outside science.
  • Edges of the periodic table: Although it sits among the halogens, relativistic effects are predicted to make it more metallic than a typical halogen. Its decay chains have also revealed new isotopes, such as lawrencium-266.

Isotopes

There are no stable isotopes. Only two isotopes are known, tennessine-293 and tennessine-294, each with a half-life of the order of tens of milliseconds. The decay chain of tennessine-294 runs through moscovium, nihonium, roentgenium and meitnerium.

In everyday life

It does not exist in nature; only a few atoms at a time are made in accelerators and they decay almost immediately, so it has no connection with daily life or health.

Good to know

  • Tennessine is the most recently discovered element.
  • The roughly 22 milligrams of berkelium-249 for the target were made in the United States and shipped to Russia.
  • Its name ends in -ine, following the halogen tradition.

Same group (17)

FFluorineClChlorineBrBromineIIodineAtAstatine

Data sources · Properties: PubChem Periodic Table (US NIH/NLM public data) · Atomic weights: CIAAW 2024 abridged standard atomic weights · Names: Wikidata (CC0); Korean names follow the Korean Chemical Society. Retrieved 2026-09-23.