Chemical element · Atomic number 111
Roentgenium
Roentgenium in the periodic table: atomic number 111, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.
Transition metal
expected to be solid
[282.169] u
Generated illustrationGenerated illustration, Quanta Study. Not a photograph of a sample.
Generated illustration of Roentgenium; 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.
Atomic classification
Shell occupancy
Roentgenium 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
- 17 electrons
- Q · n=7
- 2 electrons
- Electron configuration
- [Rn]7s2 5f14 6d9 (predicted)
- Electrons per shell
- 2 · 8 · 18 · 32 · 32 · 17 · 2
- Group
- 11
- Period
- 7
- Block
- D
- Element category
- Transition metal
Physical and chemical properties
- Atomic mass
- [282.169] u
- Standard state
- expected to be solid
- Density
- not reported
- Melting point
- not reported
- Boiling point
- not reported
- Electronegativity
- not reported
- First ionisation energy
- not reported
- Oxidation states
- +5, +3, +1, -1
- Discovery
- 1994
Safety and periodic classification
Safety
Safe handling cannot be inferred from Roentgenium'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
Roentgenium is in period 7, group 11 and the D block. Its direct neighbours by atomic number are Darmstadtium and Copernicium. 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 Roentgenium sits among the 118 elements
The table compares the reported values for Roentgenium 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 Roentgenium. 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 Roentgenium in the periodic table
- Place in the table
- Group 11, period 7, D block. Classified as transition metal, expected to be solid at standard conditions.
- Direct neighbours
- Atomic number 111. Preceded by Darmstadtium, followed by Copernicium.
- Same group
- Same number of outer electrons, and therefore similar reactivity to Copper, Silver, Gold.
- Discovery
- Recorded in the snapshot as: 1994. 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
- +5, +3, +1, -1. They follow from the electron configuration [Rn]7s2 5f14 6d9 (predicted) and indicate which compounds to expect.
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