104[267]RfRutherfordium
Rutherfordium (Rf) — element 104transition metal · group 4, period 7
Rutherfordium is a chemical element with the symbol Rf and atomic number 104. It is a transition metal in group 4, period 7 of the periodic table (the d-block), with a standard atomic mass of [267] u. At room temperature (25 °C) rutherfordium is predicted to be a solid.
💡 Known for: The first transactinide element, named after the physicist Ernest Rutherford.
# Rutherfordium properties
| Symbol | Rf |
|---|---|
| Atomic number | 104 |
| Atomic mass | [267] u |
| Category | transition metal |
| Group | 4 |
| Period | 7 |
| Block | d-block |
| Electron configuration | [Rn] 5f¹⁴ 6d² 7s² |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d² 7s² |
| Electrons per shell | 2, 8, 18, 32, 32, 10, 2 |
| Protons / electrons | 104 / 104 |
| State at 25 °C | predicted solid |
| Melting point | 2400 K (2126.8 °C, 3860.3 °F) (predicted) |
| Boiling point | 5800 K (5526.9 °C, 9980.3 °F) (predicted) |
| Density | 23.2 g/cm³ (predicted) |
| Electronegativity (Pauling) | — |
| First ionization energy | 6.0 eV |
| Atomic radius | — |
| Discovered | 1964 |
Values for superheavy elements are theoretical predictions; none have been measured in bulk.
# Electron configuration of rutherfordium
The electron configuration of rutherfordium is [Rn] 5f¹⁴ 6d² 7s², written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d² 7s². Its 104 electrons fill 7 shells as 2, 8, 18, 32, 32, 10, 2, so the outermost shell holds 2 electrons. Because only a few atoms have ever been made, this configuration is a theoretical prediction.
# Related elements
LrLawrenciumprevious elementDbDubniumnext elementTiTitaniumgroup 4ZrZirconiumgroup 4HfHafniumgroup 4ScScandiumtransition metalVVanadiumtransition metalCrChromiumtransition metalMnManganesetransition metalFeIrontransition metalCoCobalttransition metalNiNickeltransition metalCuCoppertransition metal
# Rutherfordium FAQ
What is the atomic number of rutherfordium?
The atomic number of rutherfordium is 104: every rutherfordium atom has 104 protons in its nucleus. Its symbol is Rf.
What is the atomic mass of rutherfordium?
The standard atomic mass of rutherfordium is [267] u (the mass number of its longest-lived isotope, since it has no stable isotopes).
What is the electron configuration of rutherfordium?
Rutherfordium's electron configuration is [Rn] 5f¹⁴ 6d² 7s² (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d² 7s²), with 2, 8, 18, 32, 32, 10, 2 electrons per shell.
Is rutherfordium a metal?
Yes. Rutherfordium is a transition metal, one of the metals.
What is the melting point of rutherfordium?
Rutherfordium melts at 2400 K (2126.8 °C, 3860.3 °F) and boils at 5800 K (5526.9 °C, 9980.3 °F). These values are predictions.
What is rutherfordium used for / known for?
The first transactinide element, named after the physicist Ernest Rutherford.