Silver bromide made photography possible. Write its formula and the charge logic.
Ag+ and Br- pair one-to-one: AgBr. Light kicks an electron from Br- to Ag+, seeding metallic silver specks — the latent image a developer then amplifies.
What Is the Charge of Bromine?
Bromine commonly forms Br- Br+ Br5+ in introductory ionic compounds.
Bromine takes one electron and becomes bromide, Br-, in salts like NaBr and AgBr — the light-sensitive crystal of classic photography. With oxygen it reaches +1 (hypobromite), +5 (bromate, BrO3-), but -1 is the answer for any ionic-formula problem.
| Element | Bromine |
|---|---|
| Symbol | Br |
| Atomic number | 35 |
| Common ionic charge | -1, +1, +5 |
| Common ions | Br-, Br+, Br5+ |
Visual reference
Bromine element image and atomic model
Images are used as visual references; charge rules still depend on the compound.
Why Bromine pulls one electron in
Bromine is [Ar]3d10 4s2 4p5 — the halogen signature of one missing electron. It is less electronegative than chlorine (2.96), so its positive oxidation states are less stable, and +7 perbromate is so hard to make it wasn't synthesized until 1968.
The Bromine mix-up to watch for
Treating elemental bromine and bromide interchangeably in safety terms. Br2 is a fuming, corrosive red-brown liquid — one of only two liquid elements at room temperature. Br-, by contrast, is so tame it was once prescribed as a sedative ('taking bromide').
Worked example: Br in a formula problem
Br- and Br+ and Br5+ in real compounds
NaBr
sodium bromine compound
Sodium ions can balance Br- in simple ionic examples.
CaBr2
calcium bromine compound
Calcium ions can balance common negative Bromine ions.
Questions students ask about bromine
Why did flame retardants use bromine's -1 state?
They don't, exactly — brominated flame retardants bond bromine covalently to carbon (oxidation state -1 formally). Fire heat releases bromine radicals that quench the flame's chain reactions.
What is bromate doing in drinking-water regulations?
Ozonating water that contains natural bromide can oxidize Br- (-1) to bromate BrO3- (+5), a suspected carcinogen — so utilities monitor it. A charge change, courtesy of disinfection, creates the issue.
Is bromine in pools different from chlorine in pools?
Same strategy, one row apart: the sanitizer is hypobromous acid (Br +1), which falls to bromide (-1) as it kills microbes. Bromine tolerates hot-tub temperatures better than chlorine's version.
How do I use this charge in formulas?
Combine positive and negative ions so the total charge is zero — or let the ionic compound calculator do the crossing for you. The full chart lives on the periodic table with charges.
Where this data comes from
Charges and element facts on this page are checked against the primary references below. Found an error? Email hello@periodictablewithcharges.com — corrections ship in the next content update. See how this site is edited.