Strontium (Sr)

Strontium (Sr) is element 38, an alkaline earth metal. Atomic mass 87.62, configuration [Kr] 5s². Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.

Open Strontium in the interactive periodic table

Key facts

Atomic number38
SymbolSr
Standard atomic weight87.62(1)
CategoryAlkaline Earth Metal
Group2
Period5
State at room temperatureSolid
Electron configuration[Kr] 5s²
Valence electrons2
Common oxidation states+2
Common ionsNo common ions
Electronegativity (Pauling)0.95
First ionization energy550 kJ/mol
Electron affinity4.631 kJ/mol
Atomic radius219 pm
Density2.64 g/cm³
Melting point768°C
Boiling point1382°C
Specific heat0.306 J/(g·°C)

Natural isotopes

Common uses

Where it matters

Hazards

History

Discovered1790 (identified); 1808 (isolated)
Discovered byAdair Crawford (Id.); Humphry Davy (Iso.)
NameFrom Strontian, Scotland