44101.07RuRuthenium
Ruthenium (Ru) — element 44transition metal · group 8, period 5
Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a transition metal in group 8, period 5 of the periodic table (the d-block), with a standard atomic mass of 101.07 u. At room temperature (25 °C) ruthenium is a solid.
💡 Known for: Hardens platinum and palladium alloys and is used in electrical contacts.
# Ruthenium properties
| Symbol | Ru |
|---|---|
| Atomic number | 44 |
| Atomic mass | 101.07 u |
| Category | transition metal |
| Group | 8 |
| Period | 5 |
| Block | d-block |
| Electron configuration | [Kr] 4d⁷ 5s¹ |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁷ 5s¹ |
| Electrons per shell | 2, 8, 18, 15, 1 |
| Protons / electrons | 44 / 44 |
| State at 25 °C | solid |
| Melting point | 2607 K (2333.8 °C, 4232.9 °F) |
| Boiling point | 4423 K (4149.9 °C, 7501.7 °F) |
| Density | 12.37 g/cm³ |
| Electronegativity (Pauling) | 2.2 |
| First ionization energy | 7.361 eV |
| Atomic radius | 178 pm |
| Discovered | 1844 |
# Electron configuration of ruthenium
The electron configuration of ruthenium is [Kr] 4d⁷ 5s¹, written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁷ 5s¹. Its 44 electrons fill 5 shells as 2, 8, 18, 15, 1, so the outermost shell holds 1 electron.
# Related elements
TcTechnetiumprevious elementRhRhodiumnext elementFeIrongroup 8OsOsmiumgroup 8HsHassiumgroup 8ScScandiumtransition metalTiTitaniumtransition metalVVanadiumtransition metalCrChromiumtransition metalMnManganesetransition metalCoCobalttransition metalNiNickeltransition metalCuCoppertransition metal
# Ruthenium FAQ
What is the atomic number of ruthenium?
The atomic number of ruthenium is 44: every ruthenium atom has 44 protons in its nucleus. Its symbol is Ru.
What is the atomic mass of ruthenium?
The standard atomic mass of ruthenium is 101.07 u.
What is the electron configuration of ruthenium?
Ruthenium's electron configuration is [Kr] 4d⁷ 5s¹ (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁷ 5s¹), with 2, 8, 18, 15, 1 electrons per shell.
Is ruthenium a metal?
Yes. Ruthenium is a transition metal, one of the metals.
What is the melting point of ruthenium?
Ruthenium melts at 2607 K (2333.8 °C, 4232.9 °F) and boils at 4423 K (4149.9 °C, 7501.7 °F).
What is ruthenium used for / known for?
Hardens platinum and palladium alloys and is used in electrical contacts.