Meitnerium

Unknown properties · atomic number 109

109278MtMeitneriumSolidUnknown properties

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.

Properties of Meitnerium

Element category	Unknown properties
Atomic number	109
Atomic mass	278 u
Phase at STP	Solid
Group	9
Period	7
Block	d
Electron configuration	*[Rn] 5f14 6d7 7s2
Electrons per shell	2, 8, 18, 32, 32, 15, 2
Density	37.4 g/cm3
Discovered by	Gesellschaft für Schwerionenforschung

← Hassium · Periodic table · Darmstadtium → Ds

About the unknown properties group

Superheavy synthetic elements made atom-by-atom, existing for fractions of a second; their true chemistry is still unmeasured.

Data: Periodic-Table-JSON (CC BY-SA 3.0) · stored statically on our server. https://en.wikipedia.org/wiki/Meitnerium

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🧪 Unknown properties

8 elements: Superheavy synthetic elements made atom-by-atom, existing for fractions of a second; their true chemistry is still unmeasured.