Element 111 · Unknown properties
Roentgenium (Rg) — Element 111
Wilhelm Röntgen
Roentgenium (Rg) is a chemical element with unknown bulk chemical properties in Period 7, Group 11 of the periodic table with atomic number 111, standard atomic weight [282] u, and ground-state electron configuration [Rn] 5f¹⁴ 6d⁹ 7s². At standard temperature and pressure it is classified as a short-lived synthetic nuclide with 11 valence electrons.
Research only
What are the atomic properties and physical constants of Roentgenium?
Reference constants compiled from IUPAC standard atomic weights, the NIST Atomic Spectra Database, and the CRC Handbook.
- Atomic number (Z)
- 111
- Standard atomic mass
- [282] u
- Chemical family
- Unknown properties
- Ground-state configuration
- [Rn] 5f¹⁴ 6d⁹ 7s²
- Electrons per shell
- 2, 8, 18, 32, 32, 17, 2
- Valence electrons
- 11
- Common ion charges / oxidation states
- —
- Phase at STP
- Synthetic
- Pauling electronegativity
- —
- First ionization energy
- —
- Atomic radius
- —
- Melting point
- —
- Boiling point
- —
- Discovery year
- 1994
- Table coordinate
- Period 7, Group 11
- Radioactivity
- Radioactive (no stable isotopes)
How are electrons arranged across Roentgenium’s shells?
A neutral Roentgenium atom contains 111 electrons distributed across 7 occupied principal energy shells ([Rn] 5f¹⁴ 6d⁹ 7s²). The table below compares Roentgenium’s shell occupancy against each shell’s theoretical 2n² capacity.
| Principal Shell (n) | Spectroscopic Letter | Electrons in Rg | Max Shell Capacity (2n²) |
|---|---|---|---|
| n = 1 | K | 2 e⁻ | 2 e⁻ |
| n = 2 | L | 8 e⁻ | 8 e⁻ |
| n = 3 | M | 18 e⁻ | 18 e⁻ |
| n = 4 | N | 32 e⁻ | 32 e⁻ |
| n = 5 | O | 32 e⁻ | 50 e⁻ |
| n = 6 | P | 17 e⁻ | 72 e⁻ |
| n = 7 | Q | 2 e⁻ | 98 e⁻ |
Frequently Asked Questions about Roentgenium (Rg)
What is the atomic mass and atomic number of Roentgenium (Rg)?
Roentgenium (Rg) has atomic number Z = 111 (111 protons in its nucleus) and an IUPAC standard atomic weight of [282] u. It sits in Period 7, Group 11 and is classified as an unknown properties.
What is the ground-state electron configuration of Roentgenium?
The neutral ground-state electron configuration of Roentgenium (Z = 111) is [Rn] 5f¹⁴ 6d⁹ 7s². Across its 7 occupied principal shells (n = 1 to n = 7), the electrons per shell are 2, 8, 18, 32, 32, 17, 2, with 11 valence electrons participating in bonding.
What are the common ion charges and electronegativity of Roentgenium?
Roentgenium has no common simple monatomic ion charges under standard classroom conditions. Its Pauling electronegativity is — and its first ionization energy is —.
When was Roentgenium discovered and what is it used for?
Roentgenium was discovered in 1994 (Wilhelm Röntgen). Research only
How does Roentgenium compare to neighboring elements?
Other unknown properties elements: