Roentgenium

Element 111 · Transition metal

Specimen

Atomic number: 111
Atomic mass: 282.169
State at room temperature: Unknown
Melting point: Unknown
Boiling point: Unknown
Density: Unknown
Discovered: 1994

Physical data from PubChem.¹

Can I eat it?

In food and water: Never made in amounts you could eat. Only a few atoms of roentgenium have ever been made, and they decay fast. ²

The atom

Shell	Electrons
1 (K)	2
2 (L)	8
3 (M)	18
4 (N)	32
5 (O)	32
6 (P)	17
7 (Q) outermost	2
Total	111

Configuration [Rn] 5f¹⁴ 6d⁹ 7s²

5f ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓

6d ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑

7s ↑ ↓

A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 111 protons. The outermost shell is shown in red. Electrons do not travel on rings: they fill orbitals, regions where an electron is likely to be found. The boxes are those orbitals for the electrons outside the Rn core, with one arrow per electron. This configuration is a prediction; it has not been measured.

Related elements

Sources

1

National Center for Biotechnology Information (PubChem), 2026. Periodic Table of Elements .

Atomic mass, electron configuration, melting and boiling points, density and discovery year for all 118 elements.
2
Los Alamos National Laboratory, Periodic Table of Elements, 2026. Roentgenium .
- Because so little roentgenium has ever been made (and because the atoms decay quickly), scientists can only speculate about the element’s properties.

Specimen

Can I eat it?

The atom

Related elements

New elements by e-mail

Sources