Meitnerium (symbol Mt, atomic number 109) is a synthetic superheavy element named after Lise Meitner. It is classified as a transition metal and sits in group 9, period 7 of the periodic table.
Overview
Meitnerium is the chemical element with atomic number 109 and the symbol Mt. With a standard atomic weight of [278], it is a transition metal. In the periodic table it occupies group 9 and period 7, and under standard conditions it is normally a solid. Meitnerium is a synthetic superheavy element named after Lise Meitner.
Atomic structure
An atom of Meitnerium has 109 protons in its nucleus and, when neutral, 109 electrons arranged in the configuration [Rn] 5f14 6d7 7s2. Meitnerium has no stable isotope; the value [278] refers to the mass number of its most stable or most commonly produced isotope.
Discovery and place in the table
Meitnerium was discovered in 1982 by Gesellschaft für Schwerionenforschung. It follows Hassium (Hs) and precedes Darmstadtium (Ds) in order of atomic number.
| Atomic number | 109 |
|---|---|
| Symbol | Mt |
| Atomic mass | [278] |
| Category | Transition metal |
| Group | 9 |
| Period | 7 |
| Electron configuration | [Rn] 5f14 6d7 7s2 |
| Phase at STP | Solid |
| Discovered | 1982 (Gesellschaft für Schwerionenforschung) |