Strontium (Sr)
Strontium is the chemical element with atomic number 38 and symbol Sr. It is a alkaline earth metal in period 5, group 2, with a standard atomic weight of 87.62 u.
Key facts
- Z
- 38
- Atomic weight
- 87.62 u
- Category
- alkaline earth metal
- State at 298 K
- Solid
- Occurrence
- primordial
- Discovered
- 1787
- CAS
- 7440-24-6
Measured properties
| Property | Value | Source |
|---|---|---|
| Electronegativity | 0.95 | National Center for Biotechnology Information (NIH) |
| Melting point | 1,050 K | National Center for Biotechnology Information (NIH) |
| Boiling point | 1,655 K | National Center for Biotechnology Information (NIH) |
| Density stp | 2.64 g/cm³ | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 249 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 549.5 kJ/mol | National Center for Biotechnology Information (NIH) |
Electron configuration
- Noble gas notation
- [Kr] 5s²
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s²
- Electrons per shell
- 2, 8, 18, 8, 2