Tennessine (Ts)
Element 117 · Halogen · atomic mass [294] u · group 17, period 7
Electron shells: 2, 8, 18, 32, 32, 18, 7
Tennessine was the second-to-last gap in period 7 to be filled, completing the halogen column. Making it required berkelium that had to be flown from Tennessee to Russia before it decayed.
The berkelium target had a 320-day half-life, so the whole experiment was a race against the clock.
- Atomic number
- 117
- Atomic mass
- [294] u
- Electron configuration
- [Rn] 7s² 7p⁵ 5f¹⁴ 6d¹⁰
- Group · period · block
- 17 · 7 · p
- Oxidation states
- −1, +1, +3, +5
- Electronegativity
- Not measured
- Melting point
- —
- Boiling point
- —
- Density
- Not measured
- State at 20 °C
- Unknown
- Appearance
- Unknown; presumed solid
- Discovered
- Joint Institute for Nuclear Research, Oak Ridge and Lawrence Livermore, 2010
117 protons, and 117 electrons when neutral
Mass number of the longest-lived isotope — no standard atomic weight exists
Predicted, not measured
Halogens
What Tennessine is used for
- Scientific research only
Atomic structure of Tennessine
A neutral tennessine atom has 117 protons and 117 electrons. Its most common isotope carries about 177 neutrons, which is where the mass number 294 comes from. Change the neutron count and you have a different isotope of tennessine; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8, 18, 32, 32, 18, 7. In orbital notation that is [Rn] 7s² 7p⁵ 5f¹⁴ 6d¹⁰, leaving 7 valence electrons in the outer shell — the ones that do the chemistry.
3D electron orbitals
See where Tennessine's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Tennessine sits in the periodic table
Group 17, one electron short of a full shell, which makes them aggressive oxidisers. They form salts directly with metals — "halogen" literally means salt-former.
- Directly above: Astatine — same group, so similar chemistry with a smaller atom.
- One proton lighter: Livermorium.
- One proton heavier: Oganesson.
Discovery and naming
Tennessine was discovered by Joint Institute for Nuclear Research, Oak Ridge and Lawrence Livermore in 2010. Its name comes from Tennessee, home of Oak Ridge National Laboratory, which is also why its symbol (Ts) does not match its English name.
Every isotope of tennessine is radioactive, so it has no standard atomic weight. Periodic tables show the mass number of its longest-lived isotope in square brackets instead.
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Tennessine?
Tennessine has no stable isotope, so it has no standard atomic weight. Periodic tables instead show 294 in square brackets — the mass number of its longest-lived isotope.
How many protons, neutrons and electrons does Tennessine have?
Tennessine has 117 protons, because the atomic number is the proton count and that is what makes an atom Tennessine at all. A neutral Tennessine atom has the same number of electrons, 117. The neutron count varies by isotope; the most common one has about 177, since 294 − 117 = 177.
What is the electron configuration of Tennessine?
The electron configuration of Tennessine is [Rn] 7s² 7p⁵ 5f¹⁴ 6d¹⁰, though for an element this heavy the configuration is predicted from theory rather than measured. Its electrons are arranged 2, 8, 18, 32, 32, 18, 7 across 7 shells.
Is Tennessine a metal?
No. Tennessine is classified as a halogen, on the right-hand side of the table where elements gain or share electrons rather than losing them.
What group and period is Tennessine in?
Tennessine is in group 17 (the halogens), period 7, in the p-block. The group is its column and the period is its row.
What is the charge of Tennessine?
Tennessine most commonly forms a 1− or 1+ ion. It is 1 electron short of a full outer shell, so it gains one rather than losing 7. Across all its compounds it shows oxidation states of −1, +1, +3, +5.
What is Tennessine used for?
Scientific research only. Tennessine was the second-to-last gap in period 7 to be filled, completing the halogen column.
Who discovered Tennessine, and where does its name come from?
Tennessine (Ts) was discovered by Joint Institute for Nuclear Research, Oak Ridge and Lawrence Livermore in 2010. The name comes from Tennessee, home of Oak Ridge National Laboratory.
Is Tennessine radioactive?
Yes. Every isotope of Tennessine is radioactive — it has no stable form at all, which is why the periodic table shows its mass in square brackets rather than as a standard atomic weight.