Tennessine (Ts)
Element 117 · Halogen · Solid at 25 °C · Group 17, Period 7
Tennessine is a synthetic element, produced one atom at a time in particle accelerator experiments. Its isotopes decay within moments, so none of its bulk properties have ever been measured directly — the values chemists cite for it are theoretical predictions. It is named for the U.S. state of Tennessee, home of Oak Ridge National Laboratory.
On the periodic table, tennessine sits in group 17 — the halogens — in period 7. It is one of 6 elements classified as a halogen, and at room temperature (25 °C) it is a solid.
The halogens of group 17 are one electron short of a full outer shell, which makes them ferociously good at grabbing electrons from other elements. Their name means “salt-former”: they combine with metals to make salts such as sodium chloride. They exist as diatomic molecules, and the group is the only one to span gas, liquid, and solid at room temperature. Reactivity decreases down the group.
Properties of tennessine
| Atomic number (Z) | 117 |
|---|---|
| Symbol | Ts |
| Atomic mass | (294) (mass number of the most stable isotope; this element has no standard atomic weight) |
| Category | Halogen |
| Group | 17 |
| Period | 7 |
| Block | p-block |
| Metal / nonmetal | Nonmetal |
| State at 25 °C | Solid |
| Electron configuration | [Rn] 5f14 6d10 7s2 7p5 |
| Electronegativity (Pauling) | — |
| Melting point | — |
| Boiling point | — |
| Density | — |
Position in the periodic table
Tennessine shares group 17 — the halogens with Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At). Elements in the same group have the same number of outer electrons, so they tend to behave alike chemically — comparing them is one of the fastest ways to see periodic trends in action.
Physical properties
No melting point, boiling point, or density has been measured for tennessine: too few atoms have ever existed at once. Published figures for these properties are theoretical estimates, so this site shows them as dashes rather than presenting predictions as data.
Data notes
The atomic mass is shown in parentheses because this element has no standard atomic weight; the number given is the mass number of its most stable known isotope.
The state and electron configuration listed for this element are predicted values — it has never been produced in quantities large enough to observe directly.
See also: the interactive periodic table, how to read the periodic table, the element families tour.