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38 Sr Strontium 87.62

Alkaline-earth metal

Strontium 锶

[Kr] 5s²

  • Period 5
  • Group 2
  • Block s
  • Solid

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s²

Orbital diagram (valence)

5s ↑↓
Electrons per shell
2, 8, 18, 8, 2
Unpaired electrons
0
Zeff (Slater)
2.85

Properties

Atomic weight
87.62
Electronegativity (Pauling)
0.95
First ionization energy
549.5 kJ/mol
Electron affinity
no data
Covalent radius
195 pm
van der Waals radius
249 pm
Melting point
1050 K
Boiling point
1655 K
Density
2.64 g/cm³
Melting / boiling point
776.9 °C / 1381.8 °C
Common oxidation states
+2
Discovered
1790

Emission spectrum

Strontium flame · crimson red

Explore in the spectroscope lab

Strontium in the course

The lessons that discuss this element most (ranked by mentions).

Lab experiments with Strontium

Crystal structures

  • SrTiOX3\ce{SrTiO3} Perovskite lattice parameter a = 390.5 pm
View in the crystal atlas

Periodic trend

H: 1312 kJ/molHe: 2372 kJ/molLi: 520.2 kJ/molBe: 899.5 kJ/molB: 800.6 kJ/molC: 1086 kJ/molN: 1402 kJ/molO: 1314 kJ/molF: 1681 kJ/molNe: 2081 kJ/molNa: 495.8 kJ/molMg: 737.7 kJ/molAl: 577.6 kJ/molSi: 786.5 kJ/molP: 1012 kJ/molS: 999.6 kJ/molCl: 1251 kJ/molAr: 1521 kJ/molK: 418.8 kJ/molCa: 589.8 kJ/molSc: 633 kJ/molTi: 658.8 kJ/molV: 650.9 kJ/molCr: 652.9 kJ/molMn: 717.3 kJ/molFe: 762.4 kJ/molCo: 760.4 kJ/molNi: 737.1 kJ/molCu: 745.4 kJ/molZn: 906.4 kJ/molGa: 578.8 kJ/molGe: 762.2 kJ/molAs: 947 kJ/molSe: 940.9 kJ/molBr: 1140 kJ/molKr: 1351 kJ/molRb: 403 kJ/molSr: 549.5 kJ/molY: 599.8 kJ/molZr: 640.1 kJ/molNb: 652.1 kJ/molMo: 684.3 kJ/molTc: 702.4 kJ/molRu: 710.2 kJ/molRh: 719.7 kJ/molPd: 804.4 kJ/molAg: 731 kJ/molCd: 867.8 kJ/molIn: 558.3 kJ/molSn: 708.6 kJ/molSb: 833.6 kJ/molTe: 869.3 kJ/molI: 1008 kJ/molXe: 1170 kJ/molCs: 375.7 kJ/molBa: 502.9 kJ/mol 0510152025303540455055Atomic number Z05001000150020002500First ionization energy / kJ/mol

Group 2

Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).