35BrBromine79.904 u
Bromine (Br)
Bromine is a halogen with atomic number 35, in period 4 and group 17 of the periodic table. Its atomic mass is 79.904 u and its electron configuration is [Ar] 3d¹⁰ 4s² 4p⁵. Liquid at 25 °C.
Key facts
| Atomic number | 35 |
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| Atomic mass | 79.904 u |
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| Category | Halogen |
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| Period | 4 |
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| Group | 17 |
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| Block | p |
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| Electron configuration | [Ar] 3d¹⁰ 4s² 4p⁵ |
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| Electrons per shell | 2, 8, 18, 7 |
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| Electronegativity (Pauling) | 2.96 |
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| Oxidation states | −1, +1, +2, +3, +4, +5, +7common in bold |
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| State at 25 °C | Liquid |
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| Melting point | 265.8 K−7.35 °C |
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| Boiling point | 332 K58.85 °C |
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| Density | 3.12 g/cm³ |
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Atomic properties
| First ionization energy | 11.814 eV |
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| Electron affinity | 324.6 kJ/mol |
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| Atomic radius | 115 pm |
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| Covalent radius | 120 pm |
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| Van der Waals radius | 185 pm |
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| Common ions | Br⁻ |
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| Protons, neutrons, electrons | 35, 45, 35 |
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Physical and thermal properties
| Molar volume | 19.78 cm³/mol |
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| Heat of fusion | 5.8 kJ/mol |
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| Heat of vaporization | 14.8 kJ/mol |
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| Specific heat | 947.3 J/(kg·K) |
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| Thermal conductivity | 0.12 W/(m·K) |
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| Thermal expansion | --- |
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| Mohs hardness | --- |
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| Young’s modulus | --- |
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| Crystal structure | Base orthorhombic |
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| Magnetic type | Diamagnetic |
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Identification and history
| CAS number | 7726-95-6 |
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| Latin name | Bromum |
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| Discovered by | Antoine Jérôme Balard · 1826 |
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| Named by | --- |
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Natural isotopes
| Isotope | Mass (u) | Abundance |
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| 79Br | 78.918338 | 50.65 % |
| 81Br | 80.916288 | 49.35 % |
Data checked against PubChem (NIH), IUPAC, the NIST Atomic Spectra Database and the IAEA (NUBASE and AME), the same data you see in the app.
A dash (---) means there is no reliable published measurement. The app never makes one up.
See Bromine in the app
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Periodic Table