109 Mt 278

Meitnerium

unknown, probably transition metal

Properties

Atomic number
109
Atomic mass
278 u
Category
unknown, probably transition metal
Group
9
Period
7
Block
d-block
State (room temp)
Solid
Outer-shell electrons
2
Electronegativity
Density
37.4 g/cm³
Melting point
Boiling point

Electron configuration

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

Noble-gas shorthand: [Rn] 5f¹⁴ 6d⁷ 7s²

Electrons per shell: 2, 8, 18, 32, 32, 15, 2 — that's 2 in the outermost shell.

See how electron configuration is built →

Mt
Bohr model — outer-shell electrons in blue

About Meitnerium

Meitnerium 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.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.