035Reactive nonmetal · Group 17 · Period 4
Bromine
Bromine (Br) is element 35, a reactive nonmetal in the p-block — group 17, period 4. It is a liquid at room temperature with 4 electron shells (2, 8, 18, 7) and an atomic mass of 79.904 u.
- Atomic mass
- 79.90 u
- Phase · STP
- liquid
- Melting
- 266 K · -7 °C
- Boiling
- 332 K · 59 °C
- Electronegativity
- 2.96
- Density
- 3.1028 g/cm³
Photograph — Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/bromine.php
Identity
- Atomic number
- 35
- Standard atomic weight
- 79.90 u
- Category
- Reactive nonmetal
- Group
- 17 · Halogens
- Period
- 4
- Block
- p-block
- Oxidation states
- +5, +1, -1
Physical properties
- Melting point
- 266 K · -7 °C
- Boiling point
- 332 K · 59 °C
- Density
- 3.1028 g/cm³
- Molar heat capacity
- —
- Atomic radius
- 183 pm
- Electron affinity
- 324.537 kJ/mol
Atomic structure
35protons
45neutrons
35electrons
7valence e⁻
- Noble-gas notation
- [Ar] 3d10 4s2 4p5
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
- Electrons per shell
- 2, 8, 18, 7
Periodic trends
Where Bromine ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
1.1k1
2.1k2
3.5k3
4.6k4
5.8k5
8.6k6
9.9k7
18.6k8
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- 1826
- Discovered by
- Antoine Jérôme Balard
- Named by
- —
- Appearance
- —