35 Br Bromine 79.904 u

Bromine

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Period
4
Group
17
Block
p-block
Phase (STP)
Liquid

Bromine is one of only two elements that are liquid at room temperature. It is used in flame retardants, water treatment, and photography.

Appearance: Reddish-brown liquid

About Bromine

One of only two elements that are liquid at ordinary temperatures, bromine is a dense, reddish-brown halogen of atomic number 35 and atomic mass 79.904. It has a density of 3.10 g/cm³ and boils at 332 K. Seven valence electrons ([Ar] 3d10 4s2 4p5) give a high electronegativity of 2.96 and a first ionization energy of 1140 kJ/mol. Antoine Jérôme Balard discovered the element in 1826. Bromine and its compounds are used in flame retardants, water treatment, and photography. It occupies group 17, period 4, below chlorine among the halogens.

Physical Properties

Atomic Mass 79.904 u
Density 3.1028 g/cm³
Melting Point -7.3 °C
Boiling Point 58.9 °C
Phase at STP Liquid
Atomic Radius 94.0 pm

Electronic Properties

Electronegativity 2.96
Ionization Energy 1139.9 eV
Electron Affinity 324.6 eV
Valence Electrons 7

Electron Configuration

Configuration [Ar] 3d¹⁰ 4s² 4p⁵

Electron Shell Configuration

Bromine electron shell configuration Br 2e⁻ 8e⁻ 18e⁻ 7e⁻
Electron shell structure of Bromine — electrons per shell.
Shell Electrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) 7

Position in Periodic Table

Bromine position in the periodic table Br

Discovery

Discovered by: Antoine Jerome Balard
Year: 1826

Block & Period

Block

s p d f

Period

1 2 3 4 5 6 7

Periodic Table

Lanthanides Actinides

Reactions Involving Br

Bromination of Ethylene

C₂H₄ + Br₂ → C₂H₄Br₂

Organic

Chlorine Displacing Bromine from Sodium Bromide

Cl₂ + 2NaBr → 2NaCl + Br₂

Single Replacement

Chlorine Oxidation of Bromide

Cl₂ + 2Br⁻ → 2Cl⁻ + Br₂

Redox

Compounds Containing Bromine

Bromothymol Blue

C₂₇H₂₈Br₂O₅S

Hydrobromic Acid

HBr

Methyl Bromide

CH₃Br

Sodium Bromide

NaBr

More Halogen

9 F Fluorine 17 Cl Chlorine 53 I Iodine 85 At Astatine

Frequently Asked Questions

What is Bromine?
Bromine (Br) is a chemical element with atomic number 35. It is a liquid at standard temperature and pressure, classified as a halogen.
What are the key properties of Bromine?
Bromine has an atomic mass of 79.904 u, density of 3.1028 g/cm³, melting point of -7.3°C, boiling point of 58.9°C.
What is the electron configuration of Bromine?
The electron configuration of Bromine is [Ar] 3d10 4s2 4p5. It is in the p-block of the periodic table.
Who discovered Bromine?
Bromine was discovered by Antoine Jerome Balard in 1826.
What is the electronegativity of Bromine?
Bromine has an electronegativity of 2.96 on the Pauling scale.