Mt
Meitnerium
Meitnerium is a chemical element with the symbol Mt and atomic number 109. It has a mass number of 278, sits in period 7 and group 9, and is classified as a transition metal.
Properties
| Symbol | Mt |
|---|---|
| Atomic number | 109 |
| Mass number | 278 |
| Category | Transition metal |
| Group | 9 |
| Period | 7 |
| Electron configuration | [Rn] 5f14 6d7 7s2 |
| Outer-shell electrons | 2 |
The figure of 278 is a mass number rather than a measured atomic weight, because this element has no stable isotope.
Calculate with meitnerium
- Molar mass of any formula containing it
- Electron configuration, including ions
- Effective nuclear charge by Slater's rules
- Average atomic mass from isotope abundances
Group 9
Atomic weights are the IUPAC 2021 standard values, abridged to the conventional five significant figures. Group, period, category and electron configuration are derived from the atomic number rather than stored, so they cannot drift out of step with it.