Br
Bromine
Element 35 · Halogen
Bromine (Br)
Bromine is a dense, red-brown liquid halogen with a sharp, choking smell. It is one of only two elements that are liquid at room temperature.
- Halogen
- Period 4
- Group 17
- p-block
- liquid at room temperature
Key properties
- Atomic mass
- 79.9
- u
- Electron configuration
- [Ar] 3d10 4s2 4p5
- Melting point
- -7.2 °C
- 265.95 K
- Boiling point
- 58.8 °C
- 331.95 K
- Density
- 3.11 g/cm³
- Electronegativity
- 2.96
- Pauling
- Atomic radius
- 183 pm
- van der Waals
- 1st ionisation energy
- 11.814 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about bromine
- 01
Bromine and mercury are the only elements that are liquid at room temperature and pressure.
- 02
The ancient dye Tyrian purple is a bromine compound made from sea snails.
- 03
The Dead Sea is one of the richest sources of bromine in the world.
Applications
What is bromine used for?
- Flame retardants
- Water treatment in pools and spas
- Oil and gas drilling fluids
- Pharmaceuticals
History
Discovery & name origin
Discovered by
Year
Where
France and Germany
Name origin
Greek bromos, “stench”.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 35
- Atomic mass
- 79.9 u
- Group
- 17
- Period
- 4
- Block
- p-block
- Electron configuration
- [Ar] 3d10 4s2 4p5
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
- Electrons per shell
- 2, 8, 18, 7
- Electronegativity (Pauling)
- 2.96
- Electron affinity
- 3.365 eV
- Atomic radius (van der Waals)
- 183 pm
- Stable isotopes
- 2
Oxidation states
Highlighted: common oxidation states (+5, +1, -1).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st1,139.9
- 2nd2,103
- 3rd3,470
- 4th4,560
- 5th5,760
- 6th8,550
- 7th9,940
- 8th18,600
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Liquid
- Melting point
- 265.95 K · -7.2 °C · 19 °F
- Boiling point
- 331.95 K · 58.8 °C · 137.8 °F
- Density
- 3.11 g/cm³
- Molar heat capacity
- —
- Appearance
- —
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Bromine questions
What is Br on the periodic table?
Br is the symbol for bromine, element 35 on the periodic table. It sits in group 17, period 4, in the halogen category, and has an atomic mass of 79.9.
What is the atomic number of bromine?
Bromine has atomic number 35, so every bromine atom has 35 protons in its nucleus. Its symbol is Br and its atomic mass is 79.9.
Who discovered bromine?
Bromine was discovered by Antoine-Jérôme Balard and Carl Jacob Löwig in 1826 (France and Germany). The name comes from Greek bromos, “stench”.
What is bromine used for?
Bromine is used for: flame retardants; water treatment in pools and spas; oil and gas drilling fluids; pharmaceuticals.
Is bromine a metal?
No. Bromine is classed as a halogen.
What is the electron configuration of bromine?
The electron configuration of bromine is [Ar] 3d10 4s2 4p5. Its 35 electrons are arranged in shells as 2, 8, 18, 7.