Atomic / phase data
Br2 melting, boiling, density and isotope references are evaluated.
Br2 molecular identity
Elemental bromine is diatomic; the solid viewer is a schematic molecular packing view.
Br atom / Br2 / Br-
Atom, molecule and bromide ion are distinct species and are not conflated.
Brine geography
Pins refer to selected brine/production contexts, never native elemental bromine deposits.
The lens describes evidence status, not confidence theatre. “Unknown” is kept unknown, and teaching schematics are not presented as direct measurements.
Bromine (Br)
Bromine is element 35 and the only nonmetal that is a liquid near room temperature. Neutral Br atoms pair into Br₂ molecules, while bromide Br⁻ in salts is a different chemical species with very different behavior.
Bromine atomic number, mass, electron configuration and key properties
Bromine: quick answers
How many protons, neutrons and electrons does bromine have?
Bromine’s atomic number is 35, so every bromine atom has 35 protons, and a neutral atom also has 35 electrons. Its most common natural isotope, bromine-79, has 44 neutrons (other isotopes have different neutron counts).
What is the symbol for bromine?
The chemical symbol for bromine is Br.
Is bromine a solid, liquid or gas at room temperature?
Bromine is a liquid at room temperature (about 25 °C), one of only two elements that are.
What family (group) is bromine in?
Bromine is a halogen, in group 17, period 4 of the periodic table.
How many valence electrons does bromine have?
Bromine has 7 valence electrons, the electrons in its outer shell, which matches its position in group 17.
What is the electron configuration of bromine?
The ground-state electron configuration of bromine is [Ar] 3d¹⁰ 4s² 4p⁵.
From atomic number to chemistry
Read these as a chain of causes, not as isolated facts. Each step links to the concept hub if you want the underlying idea explained.
35 protons define bromine.
The reference ground-state configuration frames atomic and chemical behavior.
Periodic position organizes recurring trends without replacing element-specific evidence.
The teaching nucleus is one isotope, not the relative atomic mass.
Phase claims are evidence-labelled; unknown superheavy bulk boundaries are not fabricated.
Bromine in its period and family
Bromine is a Period 4 Group 17 halogen between chlorine and iodine. Its seven valence electrons make electron gain and bromide formation chemically important.
Bromine Visual Lab
Compare Br with Br⁻, inspect a ⁷⁹Br nucleus and 4p orbitals, rotate a Br₂ molecular-crystal teaching view, then follow temperature through solid/liquid/vapor and connect natural brines to bromine chemistry.
Every mark points to one exact feature
The numbered markers explain the same information system used throughout Element Lookup. Unknown or predicted fields remain visibly labelled rather than being replaced with guesses.
Bromine in one minute
Atomic number 35 means 35 protons.
Neutral bromine has [Ar] 3d¹⁰ 4s² 4p⁵.
Elemental bromine is Br₂ and is liquid near room temperature.
Bromide Br⁻ is not the same substance as Br₂.
Natural bromine resources are concentrated as bromide ions in seawater and brines rather than pools of elemental Br₂.
Shell rings organize electron counts. They are not electron trajectories or orbital shapes.
2 · 8 · 18 · 7 electrons
The 4s and 4p probability models describe an isolated-atom teaching approximation. pₓ/pᵧ/p𝓏 controls rotate the same orbital shape; they do not represent a Br₂ bond by themselves.
Below its melting point bromine forms a molecular crystal of Br₂ units. The viewer emphasizes diatomic identity and packing rather than claiming refined crystallographic coordinates.. The viewer is evidence-aware: measured structures are identified as such; unknown bulk structures stay unknown.
Teaching visualization; not a literal finite sample or thermal trajectory.What this model does—and does not—show
The 4s and 4p probability models describe an isolated-atom teaching approximation. pₓ/pᵧ/p𝓏 controls rotate the same orbital shape; they do not represent a Br₂ bond by themselves.
Where do I meet bromine?
Clickable learning cards connect the element to materials, environment, technology, biology or research - depending on what the evidence actually supports.
Br₂ liquid
Elemental bromine is a dense, volatile, deep-red/brown diatomic liquid near room temperature.
Br atom → Br2 liquid → Br- ion
Bromine is ideal for separating atomic identity, molecular element and ionic chemistry.
Neutral atom
A neutral Br atom has seven valence electrons, but ordinary elemental bromine is not a monatomic liquid.
Chlorine, bromine and iodine
The halogens show a striking gas-to-liquid-to-solid progression near room temperature.
| State 20°C | Gas |
|---|---|
| Molecule | Cl₂ |
| State 20°C | Liquid |
|---|---|
| Molecule | Br₂ |
| State 20°C | Solid |
|---|---|
| Molecule | I₂ |
Bromine properties: atomic, physical, thermal and chemical
Categories follow the science of this element rather than a fixed decorative template. Each row carries condition/provenance context and an evidence label; unknown values stay unknown.
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Atomic number | 35 | Source-reviewed; see Sources below | Evaluated |
| Relative atomic mass | 79.904 | Source-reviewed; see Sources below | Evaluated |
| Ground-state electron configuration | [Ar] 3d¹⁰ 4s² 4p⁵ | Source-reviewed; see Sources below | Evaluated |
| Group / period / block | Group 17 · Period 4 · p-block | Periodic-table placement | Evaluated |
| Electronegativity | 2.96 | Source-reviewed; see Sources below | Evaluated |
| Reference isotope | ⁷⁹Br | Source-reviewed; see Sources below | Evaluated |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| State context | Deep red-brown liquid Br₂ at 20 °C | Source-reviewed; see Sources below | Evaluated |
| Density | 3.1028 g/cm³ | Source-reviewed; see Sources below | Evaluated |
| Material / molecular structure | Solid bromine · molecular Br₂ crystal | Below its melting point bromine forms a molecular crystal of Br₂ units. The viewer emphasizes diatomic identity and packing rather than claiming refined crystallographic coordinates. | Measured |
| Classification | Halogen | Periodic-table / chemistry classification | Evaluated |
| Structure-model scope | Below its melting point bromine forms a molecular crystal of Br₂ units. The viewer emphasizes diatomic identity and packing rather than claiming refined crystallographic coordinates. | Teaching visualization; exact crystallographic coordinates are not implied unless stated. | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Melting / transition reference | 266 K | Source-reviewed; see Sources below | Evaluated |
| Boiling / gas reference | 332 K | Source-reviewed; see Sources below | Evaluated |
| Phase-path context | At approximately standard pressure, Br₂ is a molecular solid below about 266 K, a liquid from about 266–332 K, and a gas above about 332 K. | Shared phase registry drives the slider, regions and markers. | Evaluated |
| Condition warning | Temperature and pressure define phase behavior; purity/allotropy may matter. | Teaching condition statement | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Common oxidation states | −1, +1, +3, +5, +7 | Source-reviewed; see Sources below | Evaluated |
| Ion / common ion context | Br⁻ | Source-reviewed; see Sources below | Evaluated |
| Periodic chemistry context | Bromine is a Period 4 Group 17 halogen between chlorine and iodine. Its seven valence electrons make electron gain and bromide formation chemically important. | Element-specific interpretation | Reviewed |
| Chemistry caution | Elemental form, ions and compounds are distinct chemical objects. | Interpretive teaching rule | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| ⁷⁹Br | Stable · about half of natural bromine | Reference teaching nucleus with 35 protons and 44 neutrons. | Evaluated |
| ⁸¹Br | Stable · about half of natural bromine | Together with 79Br gives bromine its characteristic isotope pattern in mass spectra. | Evaluated |
| Bromine isotope context | Two stable isotopes dominate nature | Their comparable abundance is a useful spectroscopy/mass-spectrometry teaching point. | Evaluated |
| Teaching nucleus | ⁷⁹Br · 35 protons + 44 neutrons | Reference isotope used in the nucleus model | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Page evidence note | Atomic/phase data are evaluated. The Br₂ crystal view is a molecular-packing teaching schematic. Geography points represent selected bromine-producing/brine regions and never imply natural pools of elemental Br₂. | Evidence summary for this guide | Reviewed |
| Structure evidence | Below its melting point bromine forms a molecular crystal of Br₂ units. The viewer emphasizes diatomic identity and packing rather than claiming refined crystallographic coordinates. | Measured structure, labelled schematic, prediction or explicit unknown as applicable. | Reviewed |
| Map evidence rule | Real pins are reviewed examples; conceptual layers are used when pins would mislead. | Geography Explorer 2.0 | Reviewed |
| Source set | 3 primary/reference links listed below | Open the Sources section for the actual references. | Reviewed |
Is Bromine a solid, liquid or gas? State at temperature
At approximately standard pressure, Br₂ is a molecular solid below about 266 K, a liquid from about 266–332 K, and a gas above about 332 K.
Where on Earth is Bromine found or produced?
Who discovered Bromine, and when?
Antoine Jérôme Balard announced bromine after isolating it from brine residues.
Carl Löwig also independently obtained bromine around the same period.
Bromine chemistry expanded into photography, dyes, pharmaceuticals and industrial intermediates.
Bromine is mainly recovered from bromide-rich brines and used through a wide range of compounds.
From bromide-rich brine to bromine chemistry: a high-level path
Bromine occurs naturally mainly as bromide ions dissolved in seawater and concentrated brines.
Commercial production uses bromide-rich brines rather than mining native elemental bromine.
Industrial conversion produces bromine and downstream bromine compounds in controlled chemical facilities; no process recipe is provided here.
Applications depend on specific bromine compounds, and environmental/safety profiles vary by chemical.
What is bromine used for?
Chemical intermediates
Bromine chemistry supports pharmaceuticals, dyes and many industrial syntheses.
Flame-retardant compounds
Selected brominated chemicals are used in flame-retardant systems; regulation and environmental behavior are compound-specific.
Water treatment
Some bromine-based compounds are used as biocides/disinfectants in controlled water-treatment settings.
Energy & specialty chemistry
Bromine chemistry appears in selected batteries, drilling fluids and other specialized applications.
Bromine isotopes and natural abundance
⁷⁹Br
Stable · about half of natural bromineReference teaching nucleus with 35 protons and 44 neutrons.
⁸¹Br
Stable · about half of natural bromineTogether with 79Br gives bromine its characteristic isotope pattern in mass spectra.
Bromine isotope context
Two stable isotopes dominate natureTheir comparable abundance is a useful spectroscopy/mass-spectrometry teaching point.
Five-question Bromine check
What is bromine’s atomic number?
What is elemental bromine near room temperature?
How many valence electrons does Br have?
What is bromide?
Where are commercial bromine resources concentrated?
Bromine questions students commonly ask
Each answer starts with the direct fact, then explains the chemistry, evidence or material context so the result is understandable rather than merely memorized.
What is bromine’s atomic number?
Short answer: 35.
Atomic number is defined by proton count, so 35 protons are what make an atom bromine. A neutral bromine atom also has 35 electrons, while isotopes can have different neutron counts without changing the element.
Key point: Atomic number = proton count.
Is bromine a metal?
Short answer: No. Bromine is a halogen nonmetal.
This guide classifies Bromine as a halogen. Its periodic position is Period 4, p-block, Group 17. Bromine is a Period 4 Group 17 halogen between chlorine and iodine. Its seven valence electrons make electron gain and bromide formation chemically important.
Key point: Periodic-table classification describes recurring atomic/chemical behavior; it does not make every element in a column physically identical.
How many valence electrons does bromine have?
Short answer: Seven, from 4s²4p⁵.
The neutral-atom ground-state reference used on this page is [Ar] 3d¹⁰ 4s² 4p⁵. This is an isolated-atom reference: bonding and ion formation can change which outer electrons are present or chemically active. The listed common oxidation-state context is −1, +1, +3, +5, +7, which helps connect the atomic configuration to ordinary chemistry without treating electron counting as a single universal rule.
Key point: Electron configuration is a ground-state atomic reference, not a literal picture of every compound.
Why is bromine liquid at room temperature?
Short answer: Bromine exists mainly as Br₂ molecules, and the intermolecular attractions between those polarizable molecules are strong enough to condense it to a liquid near room temperature but not strong enough to make it a solid there.
Down the halogen group, electron clouds become larger and more polarizable, strengthening London dispersion forces. Cl₂ is a gas near room temperature, Br₂ is a liquid, and I₂ is a solid. For bromine, the melting point is about −7.2 °C and the boiling point about 58.8 °C, so typical room temperature lies between them. Phase always depends on temperature and pressure.
Key point: The liquid state is a molecular/intermolecular-force result, not a sign that bromine atoms themselves are “liquid.”
Is bromide the same as bromine?
Short answer: No. Bromide is Br⁻; elemental bromine is primarily Br₂.
Bromine’s red-brown liquid is elemental Br₂—not “bromide.” The atom, molecule and ion share the same element but differ in electron count, bonding, state and chemical behavior. Chemical intermediates Bromine chemistry supports pharmaceuticals, dyes and many industrial syntheses.
Key point: The pure element, its ions, compounds and alloys are different materials and should not be treated as interchangeable.
Where is bromine found?
Short answer: Mostly as bromide ions in seawater, salt-lake brines and underground brines, not as native Br₂ pools.
Bromine occurs naturally mainly as bromide ions dissolved in seawater and concentrated brines. Bromide in brines Most natural bromine is present as bromide ions in seawater, salt lakes and underground brines.
Key point: Natural occurrence, resources, production and recycling are different geography questions.
Why is bromine dangerous?
Short answer: Elemental bromine (Br₂) is a volatile, corrosive and toxic molecular liquid/vapor that can injure tissues on contact or inhalation.
Do not confuse Br₂ with bromide ion, Br⁻. Bromide salts have very different chemical behavior from elemental bromine. Hazard also depends on concentration and route of exposure, so an element name alone is not a complete risk statement.
Key point: Elemental bromine and bromide are different chemical objects with different hazards.
Scientific sources for Bromine
- Royal Society of Chemistry - Bromine
- NIST - Atomic Data for Bromine
- USGS - Bromine statistics and information
- RSC — Bromine
Questions to ask next about Bromine
A good element lesson should lead to the next useful question, not end after a list of facts.
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