Bright Atoms, home
Periodic table / Halogens

35Bromine

Bromine is a halogen in group 17, period 4. At 25 °C it is a liquid.

Br
Shells: 2, 8, 18, 7. A simple picture: electrons do not move in circles.
Symbol
Br
Atomic number
35 protons in the nucleus
Standard atomic weight
79.904 ± 0.003
Electron configuration
[Ar] 3d10 4s2 4p5
Electrons in each shell
2, 8, 18, 7
Group, period, block
17, 4, p
Family
Halogens
State at 25 °C
liquid
Electronegativity
2.96 (Pauling scale)
First ionisation energy
1139.9 kJ/mol (11.81381 eV)
Where these numbers come from

Atomic weight: IUPAC CIAAW, abridged standard atomic weights 2024. Electron configuration and ionisation energy: NIST Atomic Spectra Database. Family, state and electronegativity: PubChem. See Sources. Melting points, boiling points and densities are left out for now: published values differ between sources, and we will add them once each has been checked.