Strontium
A reactive metal that colors fireworks brilliant red.
Inside the Strontium atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Strontium atom step by step.
Electron configuration
[Kr] 5s2
A neutral Strontium atom has 38 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Physical & atomic properties
- State (room temp)
- Solid
- Melting point
- 1050 K (777 °C)
- Boiling point
- 1655 K (1382 °C)
- Density
- 2.64 g/cm³
- Electronegativity
- 0.95 Pauling
- Atomic radius
- 200 pm
- 1st ionization energy
- 549 kJ/mol
- Category
- Alkaline earth metals
Discovery & naming
- Discovered
- 1790
- Discovered by
- Adair Crawford
- Origin of name
- Strontian, a village in Scotland.
Notable uses
Red fireworks, glow-in-the-dark paint, and magnets.
Where Strontium comes from
Stellar fusion and dying stars
Mostly slow neutron capture in dying low-mass stars, which pile neutrons onto iron seeds one at a time.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 38
- Atomic mass
- 87.62
- Category
- Alkaline earth metals
- Group · Period
- 2 · 5
- Block
- s-block
- Shells
- 2 · 8 · 18 · 8 · 2