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Bromine

Element 35 · Halogen

Specimen

Atomic number
35
Atomic mass
79.904
State at room temperature
Liquid
Melting point
-7.2 °C
Boiling point
58.8 °C
Density
3.11 g/cm³
Discovered
1826

Atomic mass from IUPAC.1 Other physical data from PubChem.2

Can I eat it?

In food and water
Harmful. The US FDA stopped the use of brominated vegetable oil in food in 2024. In studies in rodents, the FDA found more bromine in tissue, and harm to the thyroid at high doses. 3

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The atom

Br
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) outermost 7
Total35

Configuration [Ar] 3d¹⁰ 4s² 4p⁵

3d ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓
4s ↑ ↓
4p ↑ ↓ ↑ ↓ ↑
A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 35 protons. The outermost shell is shown in red. Electrons do not travel on rings: they fill orbitals, regions where an electron is likely to be found. The boxes are those orbitals for the electrons outside the Ar core, with one arrow per electron.

Related elements

Group 17
F Fluorine Cl Chlorine I Iodine At Astatine Ts Tennessine

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Abridged Standard Atomic Weights 2024 .

    The atomic mass shown for the 84 elements that have a standard atomic weight.

  2. 2

    National Center for Biotechnology Information (PubChem), 2026. Periodic Table of Elements .

    Electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  3. 3

    U.S. Food and Drug Administration, 2024. Brominated Vegetable Oil (BVO) .

    • The FDA no longer allows for the use of brominated vegetable oil (BVO) in food. On July 3, 2024, the FDA revoked its food additive regulation
    • oral exposure to BVO is associated with increased tissue levels of bromine and that at high levels of exposure the thyroid is a target organ of potential negative health effects in rodents
  4. 4

    National Institute of Standards and Technology (NIST), 2026. Atomic Weights and Isotopic Compositions for All Elements .

    Isotopic composition of each element; the most abundant isotope sets the neutron count in the nucleus view.