38SrStrontium87.621[Kr] 5s²
alkaline earth metal
Strontium
Strontium is a chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when it is exposed to air.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
Electrons by shell
Electron configuration
5s2
36 is the [Kr] core total across four shells.
At a glance
- Atomic number
- 38
- Atomic mass
- 87.621 u
- Phase
- Solid
- Density
- 2.64 g/cm³
- Melting point
- 1,050 K
- Boiling point
- 1,650 K
- First ionization energy
- 549.5 kJ/mol
- Electronegativity
- 0.95
- Electron affinity
- 5.023 kJ/mol
- Molar heat capacity
- 26.4 J/(mol·K)
- Period
- 5
- Appearance
- Unavailable
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.