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Bromine (Br)

Bromine is a chemical element of the periodic table with chemical symbol Br and atomic number 35 with an atomic weight of 79.901 u and is classed as nonmetal and is part of group 17 (fluorine group). Bromine is liquid at room temperature.

Bromine in the periodic table

Atomic number35
Group17 (Fluorine group)
Color Red
Number of protons35 p+
Number of neutrons45 n0
Number of electrons35 e-
From Wikipedia, the free encyclopediaBromine (from Ancient Greek:βρῶμος, brómos, meaning "stench") is a chemical element with symbol Br, and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826.

Physical properties

Phase at STPLiquid
Density3.1028 g/cm3
Atomic weight79.901 u

Thermal properties

Melting point265.8 K
-7.35 °C
18.77 °F
Boiling point332 K
58.85 °C
137.93 °F
Heat of vaporization14.725 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)2.96
Electron affinity324.537 kJ/mol
Oxidation states−1, +1, +3, +4, +5, +7
(a strongly acidic oxide)
Ionization energies
  1. 1139.9 kJ/mol
  2. 2103 kJ/mol
  3. 3470 kJ/mol
  4. 4560 kJ/mol
  5. 5760 kJ/mol
  6. 8550 kJ/mol
  7. 9940 kJ/mol
  8. 18600 kJ/mol

Electron configuration for bromine

Electron configuration
Shorthand configuration
[Ar] 3d10 4s2 4p5
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p5
Electron configuration chart
Electrons per shell2, 8, 18, 7
Valence electrons 7
Valency electrons 1,3,5
Bohr model
BromineElectron shell for Bromine, created by Injosoft ABBr
Figure: Shell diagram of Bromine (Br) atom.
Orbital Diagram

The history of Bromine

Discovery and first isolationAntoine Jérôme Balard, Carl Jacob Löwig (1825)
Discovery of bromine
Bromine was discovered independently by two chemists, Carl Jacob Löwig and Antoine Balard, in 1825 and 1826, respectively. Löwig isolated bromine from a mineral water spring from his hometown Bad Kreuznach in 1825. Löwig used a solution of the mineral salt saturated with chlorine and extracted the bromine with diethyl ether. The publication of the results was delayed and Balard published his results first. Balard found bromine chemicals in the ash of seaweed from the salt marshes of Montpellier. The seaweed was used to produce iodine, but also contained bromine. Balard distilled the bromine from a solution of seaweed ash saturated with chlorine. The properties of the resulting substance were intermediate between those of chlorine and iodine; thus he tried to prove that the substance was iodine monochloride (ICl), but after failing to do so he was sure that he had found a new element and named it muride, derived from the Latin word muria ("brine").


List of unique identifiers for Bromine in various chemical registry databases
CAS Number7726-95-6
ChemSpider ID4514586
EC number231-778-1
PubChem CID Number24408