Strontium (Sr)

Strontium is a chemical element of the periodic table with chemical symbol Sr and atomic number 38 with an atomic weight of 87.621 u and is classed as alkaline earth metal and is part of group 2 (alkaline earth metal). Strontium is solid at room temperature.

Rubidium Periodic table Yttrium

Strontium in the periodic table

Symbol	Sr
Atomic number	38
Group	2 (Alkaline earth metal)
Period	5
Block	s
Classification	Alkaline Earth Metal

Appearance	-
Color	Silver

Number of protons	38 p⁺
Number of neutrons	50 n⁰
Number of electrons	38 e^-

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.

Physical properties

Phase at STP	Solid
Density	2.64 g/cm³
Atomic weight	87.621 u

Thermal properties

Melting point	1050 K 776.85 °C 1430.33 °F
Boiling point	1650 K 1376.85 °C 2510.33 °F
Heat of vaporization	136.9 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)	0.95
Electron affinity	5.023 kJ/mol
Oxidation states	+1, +2 (a strongly basic oxide)
Ionization energies	549.5 kJ/mol 1064.2 kJ/mol 4138 kJ/mol 5500 kJ/mol 6910 kJ/mol 8760 kJ/mol 10230 kJ/mol 11800 kJ/mol 15600 kJ/mol 17100 kJ/mol 31270 kJ/mol

Electron configuration for strontium

Electron configuration

Shorthand configuration

[Kr] 5s²

Electron configuration

Full configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s²

Electron configuration chart

1s²
2s²	2p⁶
3s²	3p⁶	3d¹⁰
4s²	4p⁶
5s²

Electrons per shell

2, 8, 18, 8, 2

Valence electrons

2

Valency electrons

2

Bohr model

Figure: Shell diagram of Strontium (Sr) atom.

Orbital Diagram

1s
2s	2p
3s	3p	3d
4s	4p
5s

The history of Strontium

Discovery	William Cruickshank (1787)
First isolation	Humphry Davy (1808)
Discovery of strontium Both strontium and strontianite are named after Strontian, a village in Scotland near which the mineral was discovered in 1790 by Adair Crawford and William Cruickshank; it was identified as a new element the next year from its crimson-red flame test color. The element was eventually isolated by Sir Humphry Davy in 1808 by the electrolysis of a mixture containing strontium chloride and mercuric oxide, and announced by him in a lecture to the Royal Society on 30 June 1808. In keeping with the naming of the other alkaline earths, he changed the name to strontium.

Periodic table history

Identifiers

List of unique identifiers for Strontium in various chemical registry databases

CAS Number	7440-24-6
ChemSpider ID	4514263
EC number	231-133-4
PubChem CID Number	5359327