About

Meitnerium is a synthetic element named to honor Lise Meitner, an Austrian-Swedish physicist who was a key part of the team that discovered nuclear fission but was overlooked for the Nobel Prize. It is an extremely radioactive element of which only a few atoms have ever been synthesized. It is expected to share properties with iridium.

Atomic Properties

Atomic Number109

Atomic Weight278 u

Neutrons (common)169

Electron Configuration[Rn] 5f¹⁴ 6d⁷ 7s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d⁷ 7s²

Electrons per Shell2, 8, 18, 32, 32, 15, 2

Oxidation States+8, +6, +4, +3, +1

Periodic Table Position

Group9

Period7

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Appearancepredicted to be a silvery-white metal

Crystal Structurefcc

Magnetic Orderingparamagnetic

Discovery

Discovered byGesellschaft für Schwerionenforschung

Discovery Year1,982

Occurrencesynthetic

CAS Number54038-01-6

Electron Configuration

Energy

↿⇂

1s

↿⇂

2s

↿⇂

2p

↿⇂

3s

↿⇂

3p

↿⇂

4s

↿⇂

3d

↿⇂

4p

↿⇂

5s

↿⇂

4d

↿⇂

5p

↿⇂

6s

↿⇂

4f

↿⇂

5d

↿⇂

6p

↿⇂

7s

↿⇂

5f

↿⇂

↿

6d

7p

Isotopes of Meitnerium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
²⁷⁸Mt	278.154820	—	7.6 s	Alpha Decay