Is roentgenium a metal?

Roentgenium's chemical category has not been confirmed by experiment, so it is listed with unclassified properties.

How many protons does roentgenium have?

Roentgenium has 111 protons. Its atomic number is 111, which is also the number of electrons in a neutral atom of roentgenium.

What group and period is roentgenium in?

Roentgenium is in group 11 and period 7 of the periodic table, in the d-block.

What is the atomic mass of roentgenium?

The atomic mass of roentgenium is 282 u (unified atomic mass units).

Element 111

Roentgenium (Rg)

Element with unclassified properties · Period 7 · Group 11 · d-block

Roentgenium (Rg) is element 111 of the periodic table, an element with unclassified properties in period 7, group 11 (d-block) with an atomic mass of 282 and is a solid at standard conditions.

At a glance

Atomic number: 111
Symbol: Rg
Atomic mass: 282 u
Category: Unclassified properties
Period: 7
Group: 11
Block: d-block
Phase at STP: solid

Electron structure

Electron configuration: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 5f14 6d9 7s2
Shorthand configuration: [Rn] 5f14 6d9 7s2
Electrons per shell: 2, 8, 18, 32, 32, 17, 2
Oxidation states: +5

Physical properties

Roentgenium has only ever been produced in quantities too small to weigh or observe in bulk. The physical and atomic values below are theoretical predictions from periodic trends and relativistic calculations, not measurements.

Density: 28.7 g/cm³ (predicted)
Phase: solid

Atomic properties

Covalent radius: 121 pm (predicted)
First ionization energy: 1020 kJ/mol (predicted)
Electron affinity: 151 kJ/mol (predicted)

Notable isotopes

Notable isotopes of Roentgenium: mass number, atomic mass, natural abundance, and stability.
Isotope	Mass	Abundance	Stability
Rg-282	282.16912	-	Half-life 100 seconds

Common uses

Scientific research only

Discovery

Year: 1994
Discovered by: Sigurd Hofmann
Country: Germany

Frequently asked questions

Is roentgenium a metal?: Roentgenium's chemical category has not been confirmed by experiment, so it is listed with unclassified properties.
How many protons does roentgenium have?: Roentgenium has 111 protons. Its atomic number is 111, which is also the number of electrons in a neutral atom of roentgenium.
What group and period is roentgenium in?: Roentgenium is in group 11 and period 7 of the periodic table, in the d-block.
What is the atomic mass of roentgenium?: The atomic mass of roentgenium is 282 u (unified atomic mass units).

Keep exploring

Roentgenium's row is on the printable element property sheet, and its tile is on the periodic table wall chart - the same numbers as above, laid out for A4 or A3 paper.