3887.62SrStrontium
Strontium (Sr) — element 38alkaline earth metal · group 2, period 5
Strontium is a chemical element with the symbol Sr and atomic number 38. It is an alkaline earth metal in group 2, period 5 of the periodic table (the s-block), with a standard atomic mass of 87.62 u. At room temperature (25 °C) strontium is a solid.
💡 Known for: Gives fireworks and flares their bright red colour.
# Strontium properties
| Symbol | Sr |
|---|---|
| Atomic number | 38 |
| Atomic mass | 87.62 u |
| Category | alkaline earth metal |
| Group | 2 |
| Period | 5 |
| Block | s-block |
| Electron configuration | [Kr] 5s² |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s² |
| Electrons per shell | 2, 8, 18, 8, 2 |
| Protons / electrons | 38 / 38 |
| State at 25 °C | solid |
| Melting point | 1050 K (776.9 °C, 1430.3 °F) |
| Boiling point | 1655 K (1381.8 °C, 2519.3 °F) |
| Density | 2.64 g/cm³ |
| Electronegativity (Pauling) | 0.95 |
| First ionization energy | 5.695 eV |
| Atomic radius | 219 pm |
| Discovered | 1790 |
# Electron configuration of strontium
The electron configuration of strontium is [Kr] 5s², written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s². Its 38 electrons fill 5 shells as 2, 8, 18, 8, 2, so the outermost shell holds 2 electrons. As a group 2 element, strontium has 2 valence electrons.
# Related elements
RbRubidiumprevious elementYYttriumnext elementBeBerylliumgroup 2MgMagnesiumgroup 2CaCalciumgroup 2BaBariumgroup 2RaRadiumgroup 2
# Strontium FAQ
What is the atomic number of strontium?
The atomic number of strontium is 38: every strontium atom has 38 protons in its nucleus. Its symbol is Sr.
What is the atomic mass of strontium?
The standard atomic mass of strontium is 87.62 u.
What is the electron configuration of strontium?
Strontium's electron configuration is [Kr] 5s² (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s²), with 2, 8, 18, 8, 2 electrons per shell.
Is strontium a metal?
Yes. Strontium is an alkaline earth metal, one of the metals.
What is the melting point of strontium?
Strontium melts at 1050 K (776.9 °C, 1430.3 °F) and boils at 1655 K (1381.8 °C, 2519.3 °F).
What is strontium used for / known for?
Gives fireworks and flares their bright red colour.