#109 / 118
109Mt[278]
Superheavy / Unknownsolid at STPD-block

Meitnerium

Group: 9•Period: 7•Standard Atomic Weight: [278] u
Open Full Periodic TableView Bohr Model

Why is Meitnerium in this position?

Understanding the scientific rationale behind Meitnerium's position in the periodic table:

Group Assignment
Group 9

Belongs to Group 9 as the 6d homologue of Cobalt, Rhodium, and Iridium (6d⁷ 7s²).

Period Assignment
Period 7

Belongs to Period 7 because its outermost electrons occupy n=7.

Orbital Block
D-block

Belongs to the d-block because its valence electrons occupy 6d orbitals.

Chemical Category
Superheavy / Unknown

Classified as a superheavy transition metal.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 18, 32, 32, 15, 2]

Bohr Atomic Shell Model(2, 8, 18, 32, 32, 15, 2)

Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.

109 Protons (p⁺)169 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 8Shell L: Electron 2 of 8Shell L: Electron 3 of 8Shell L: Electron 4 of 8Shell L: Electron 5 of 8Shell L: Electron 6 of 8Shell L: Electron 7 of 8Shell L: Electron 8 of 8MShell M: Electron 1 of 18Shell M: Electron 2 of 18Shell M: Electron 3 of 18Shell M: Electron 4 of 18Shell M: Electron 5 of 18Shell M: Electron 6 of 18Shell M: Electron 7 of 18Shell M: Electron 8 of 18Shell M: Electron 9 of 18Shell M: Electron 10 of 18Shell M: Electron 11 of 18Shell M: Electron 12 of 18Shell M: Electron 13 of 18Shell M: Electron 14 of 18Shell M: Electron 15 of 18Shell M: Electron 16 of 18Shell M: Electron 17 of 18Shell M: Electron 18 of 18NShell N: Electron 1 of 32Shell N: Electron 2 of 32Shell N: Electron 3 of 32Shell N: Electron 4 of 32Shell N: Electron 5 of 32Shell N: Electron 6 of 32Shell N: Electron 7 of 32Shell N: Electron 8 of 32Shell N: Electron 9 of 32Shell N: Electron 10 of 32Shell N: Electron 11 of 32Shell N: Electron 12 of 32Shell N: Electron 13 of 32Shell N: Electron 14 of 32Shell N: Electron 15 of 32Shell N: Electron 16 of 32Shell N: Electron 17 of 32Shell N: Electron 18 of 32Shell N: Electron 19 of 32Shell N: Electron 20 of 32Shell N: Electron 21 of 32Shell N: Electron 22 of 32Shell N: Electron 23 of 32Shell N: Electron 24 of 32Shell N: Electron 25 of 32Shell N: Electron 26 of 32Shell N: Electron 27 of 32Shell N: Electron 28 of 32Shell N: Electron 29 of 32Shell N: Electron 30 of 32Shell N: Electron 31 of 32Shell N: Electron 32 of 32OShell O: Electron 1 of 32Shell O: Electron 2 of 32Shell O: Electron 3 of 32Shell O: Electron 4 of 32Shell O: Electron 5 of 32Shell O: Electron 6 of 32Shell O: Electron 7 of 32Shell O: Electron 8 of 32Shell O: Electron 9 of 32Shell O: Electron 10 of 32Shell O: Electron 11 of 32Shell O: Electron 12 of 32Shell O: Electron 13 of 32Shell O: Electron 14 of 32Shell O: Electron 15 of 32Shell O: Electron 16 of 32Shell O: Electron 17 of 32Shell O: Electron 18 of 32Shell O: Electron 19 of 32Shell O: Electron 20 of 32Shell O: Electron 21 of 32Shell O: Electron 22 of 32Shell O: Electron 23 of 32Shell O: Electron 24 of 32Shell O: Electron 25 of 32Shell O: Electron 26 of 32Shell O: Electron 27 of 32Shell O: Electron 28 of 32Shell O: Electron 29 of 32Shell O: Electron 30 of 32Shell O: Electron 31 of 32Shell O: Electron 32 of 32PShell P: Electron 1 of 15Shell P: Electron 2 of 15Shell P: Electron 3 of 15Shell P: Electron 4 of 15Shell P: Electron 5 of 15Shell P: Electron 6 of 15Shell P: Electron 7 of 15Shell P: Electron 8 of 15Shell P: Electron 9 of 15Shell P: Electron 10 of 15Shell P: Electron 11 of 15Shell P: Electron 12 of 15Shell P: Electron 13 of 15Shell P: Electron 14 of 15Shell P: Electron 15 of 15QShell Q: Electron 1 of 2Shell Q: Electron 2 of 2MtZ = 109

Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.

Electron Shell Filling Breakdown

Shell K (n=1):2 / 2 electrons (100%)
Shell L (n=2):8 / 8 electrons (100%)
Shell M (n=3):18 / 18 electrons (100%)
Shell N (n=4):32 / 32 electrons (100%)
Shell O (n=5):32 / 50 electrons (64%)
Shell P (n=6):15 / 72 electrons (21%)
Shell Q (n=7):2 / 98 electrons (2%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d⁷ 7s²

Neutral ground state configuration. Valence electrons: 9.

Atomic & Quantum Properties

Electronegativity (Pauling)Not available
1st Ionization Energy800 kJ/mol
Electron AffinityNot available
Atomic Radius (empirical)130 pm
Common Oxidation States+3, +4
Crystal StructureFCC (predicted)

Physical & Thermal Properties

Density at STP37.4 g/cm³ (predicted)
Melting Point2600 °C (2873 K)
Boiling Point6000 °C (6273 K)
Magnetic OrderingParamagnetic
Discovery Year1982
Discovered ByGSI Helmholtz Centre for Heavy Ion Research (Darmstadt, Germany)

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Pure nuclear physics research exploring heavy actinide decay chains
Occurrence in Nature

Synthesized in heavy-ion accelerators by bombarding Bismuth-209 with Iron-58 ions.

Etymology & Name Origin

Named in honor of Austrian-Swedish physicist Lise Meitner, co-discoverer of nuclear fission

Important Chemical Compounds
None (only isolated atoms produced)
Interesting Chemical Facts
  • • Meitnerium was named in honor of Lise Meitner, who first explained and calculated the colossal energy released by uranium nuclear fission in 1938.
  • • Lise Meitner is the only non-mythological woman honored solely in the naming of a chemical element (Marie Curie shares Curium with her husband Pierre).
  • • The longest-lived isotope, Meitnerium-278, has a half-life of roughly 8 seconds.
Safety & Handling Note

Highly radioactive; produced only atom by atom.

Explore Neighborhood Elements

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