Strontium (Sr)

From Wikipedia, the free encyclopediaStrontium is a chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when it is exposed to air.

Strontium in the periodic table

SymbolSr
Atomic number38
Group2
Period5
Blocks
Element categoryAlkaline Earth Metal

Physical properties

Phase at STPSolid
Density2.64 g/cm3
Atomic weight87.621 u
Melting point1050 K
776.85 °C
1430.33 °F
Boiling point1650 K
1376.85 °C
2510.33 °F

Atomära egenskaper

Electronegativity (Pauling Scale)0.95
Electron affinity5.023 kJ/mol
Ionization energies
1549.5 kJ/mol
2 1064.2 kJ/mol
3 4138 kJ/mol
4 5500 kJ/mol
5 6910 kJ/mol
6 8760 kJ/mol
7 10230 kJ/mol
8 11800 kJ/mol
9 15600 kJ/mol
10 17100 kJ/mol
11 31270 kJ/mol

Electron configuration

Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s2
Electrons per shell2, 8, 18, 8, 2

History

Discovered1787
Discovered byWilliam Cruickshank