Chemical element · Atomic number 109

Meitnerium

Meitnerium in the periodic table: atomic number 109, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.

Mt

Transition metal

solid

[277.154] u

Generated illustration of Meitnerium (Mt): an ampoule with the symbol and atomic number, not a photoGenerated illustration

Generated illustration, Quanta Study. Not a photograph of a sample.

Generated illustration of Meitnerium; the image does not show a sample of the element.

Synthetic element produced a few atoms at a time; there is no visible sample.

Code-native illustration with the Quanta Study mark inside the image; not a photograph, no AI model involved.

Licence and image notes from Quanta Study

Atomic classification

Meitnerium in the Bohr shell modelThis shows the electron distribution of the neutral atom in a simplified shell model.: 2 · 8 · 18 · 32 · 32 · 15 · 2

Shell occupancy

Meitnerium in the Bohr shell model

This shows the electron distribution of the neutral atom in a simplified shell model.

K · n=1
2 electrons
L · n=2
8 electrons
M · n=3
18 electrons
N · n=4
32 electrons
O · n=5
32 electrons
P · n=6
15 electrons
Q · n=7
2 electrons
Shell occupancy is derived from the versioned PubChem electron configuration. Dot angles are schematic and do not represent orbitals.
Electron configuration
[Rn]7s2 5f14 6d7 (calculated)
Electrons per shell
2 · 8 · 18 · 32 · 32 · 15 · 2
Group
9
Period
7
Block
D
Element category
Transition metal

Physical and chemical properties

Atomic mass
[277.154] u
Standard state
solid
Density
not reported
Melting point
not reported
Boiling point
not reported
Electronegativity
not reported
First ionisation energy
not reported
Oxidation states
+9, +8, +6, +4, +3, +1
Discovery
1982

Safety and periodic classification

Safety

Safe handling cannot be inferred from Meitnerium's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.

Position and comparison

Meitnerium is in period 7, group 9 and the D block. Its direct neighbours by atomic number are Hassium and Darmstadtium. The snapshot does not report a Pauling electronegativity. Periodic trends are compared only through the separately sourced neighbouring values.

Sources and scope

PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.

Where Meitnerium sits among the 118 elements

The table compares the reported values for Meitnerium with every other element that carries the same value in the snapshot. A rank is not a judgement, it is orientation: it says how unusual this value is across the periodic table.

The snapshot reports no measured material data for Meitnerium. That is normal for the heaviest elements, which exist only in minute quantities, and it is stated here instead of showing estimates.

All values and ranks come from the PubChem Periodic Table snapshot, retrieved on 2026-07-15. Elements without a reported value are excluded, so the population differs per row.

The neighbours of Meitnerium in the periodic table

Place in the table
Group 9, period 7, D block. Classified as transition metal, solid at standard conditions.
Direct neighbours
Atomic number 109. Preceded by Hassium, followed by Darmstadtium.
Same group
Same number of outer electrons, and therefore similar reactivity to Cobalt, Rhodium, Iridium.
Discovery
Recorded in the snapshot as: 1982. Who, where and under what circumstances is not part of that record, so this page carries the sourced year and no discovery narrative.
Oxidation states
+9, +8, +6, +4, +3, +1. They follow from the electron configuration [Rn]7s2 5f14 6d7 (calculated) and indicate which compounds to expect.

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