Hallide ions

• halides (-1 charge) = ions formed by halogen atoms when they gain one electron. E.G. Cl-, Br-, I-
• Testing for halide ions = use a reagent called silver nitrate solution; if halide ions are present, a precipiate of a silver halide is produced
• precipitate = solid formed when two solutions mix
• precipitate of AgCl=white
• precipitate of AgBr = Cream
• precipitate of AgI(iodine)= yellow
• General ionic (so no ₂) formula for halide ion test = Ag+X=AgX
• A compound has to be dissolved in water (forming a solution) before silver nitrate solution is added