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Rutherfordium

Element 104 · Transition metal

Specimen

Atomic number
104
Atomic mass
[267]
State at room temperature
Solid
Melting point
Unknown
Boiling point
Unknown
Density
Unknown
Discovered
1964

Mass number of the longest-lived isotope, from IUPAC.1 Other physical data from PubChem.2

Can I eat it?

In food and water
Never made in amounts you could eat. Laboratories make rutherfordium a few atoms at a time. A few thousand atoms have been made since 1964. 3

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The atom

Rf
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) 32
5 (O) 32
6 (P) 10
7 (Q) outermost 2
Total104

Configuration [Rn] 5f¹⁴ 6d² 7s²

5f ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓
6d ↑ ↑
7s ↑ ↓
A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 104 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

Group 4
Ti Titanium Zr Zirconium Hf Hafnium

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Radioactive Elements .

    Mass number and half-life of the longest-lived isotope of the 34 elements with no standard atomic weight.

  2. 2

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

    Electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  3. 3

    Los Alamos National Laboratory, Periodic Table of Elements, 2026. Rutherfordium .

    • Since its discovery in 1964, only a few thousand atoms of rutherfordium have ever been produced!