44RuRuthenium101.072[Kr] 4d⁷ 5s¹
transition metal
Ruthenium
Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
Electrons by shell
Electron configuration
4d7
5s1
36 is the [Kr] core total across four shells.
At a glance
- Atomic number
- 44
- Atomic mass
- 101.072 u
- Phase
- Solid
- Density
- 12.45 g/cm³
- Melting point
- 2,607 K
- Boiling point
- 4,423 K
- First ionization energy
- 710.2 kJ/mol
- Electronegativity
- 2.2
- Electron affinity
- 100.96 kJ/mol
- Molar heat capacity
- 24.06 J/(mol·K)
- Period
- 5
- Appearance
- silvery white metallic
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.