Hassium Darmstadtium

Meitnerium (Mt)

From Wikipedia, the free encyclopediaMeitnerium is a chemical element with symbol Mt and atomic number 109. It is an extremely radioactive synthetic element (an element not found in nature that can be created in a laboratory). The most stable known isotope, meitnerium-278, has a half-life of 7.6 seconds.

Meitnerium in the periodic table

Symbol

Atomic number

109

Group

Period

Block

Element category

Unknown

Physical properties

Phase at STP

Solid

Density

37.4 g/cm³

Atomic weight

278 u

Melting point

Boiling point

K
°C
°F

Atomic properties

Electronegativity (Pauling Scale)

Electron affinity

kJ/mol

Oxidation states

(+1), (+3), (+4), (+6), (+8), (+9)
(predicted)

Ionization energies

1	800.8 kJ/mol
2	1823.6 kJ/mol
3	2904.2 kJ/mol
4	3859.4 kJ/mol
5	4920.8 kJ/mol

Electron configuration

Elektronkonfiguration (shorthand)

[Rn] 5f¹⁴ 6d⁷ 7s²

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d⁷ 7s²

Electrons per shell

2, 8, 18, 32, 32, 15, 2

History

Discovered

1982

Discovered by

Gesellschaft für Schwerionenforschung