ELEMENTLE

Element 117 · Halogen

Tennessine

Period 7 · Group 17

Tennessine is a superheavy artificial chemical element with an atomic number of 117 and a symbol of Ts. Also known as eka-astatine or element 117, it is the second-heaviest known element and penultimate element of the 7th period of the periodic table. As of 2016, fifteen tennessine atoms have been observed: six when it was first synthesized in 2010, seven in 2012, and two in 2014.

Three reasons Tennessine stands out

  1. 1

    Named after US state known as the birthplace of blues.

  2. 2

    It was first synthesised in 2010, making it one of the most recently confirmed elements on the periodic table.

  3. 3

    Unlike the lighter halogens, it is predicted to have metallic rather than non-metallic properties due to relativistic effects.

A halogen unlike the halogens we can hold

Tennessine honors the Tennessee institutions that helped supply targets, data, and expertise for its discovery. It occupies the halogen column, but extreme relativistic effects may weaken the chemistry familiar from fluorine and chlorine. Every known atom has disappeared in a fraction of a second.

Tennessine at a glance
Atomic number / protons117
SymbolTs
Family (Elementle)Halogen
Classification (PubChem)Halogen
Period7
Group17
Atomic mass (u)294.211
Standard stateBulk state not experimentally established
Electron configuration[Rn]7s2 7p5 5f14 6d10 (predicted)
Reported oxidation states+5, +3, +1, -1
Electronegativity (Pauling)Not available
Atomic radius (pm)Not available
First ionization energy (eV)Not available
Electron affinity (eV)Not available
Density (g/cm³)Not available
Melting pointNot available
Boiling pointNot available
Discovery (PubChem)2010

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Tennessine · Tennessine on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.