IGCSE›Oxford AQA IGCSE Chemistry›Mind mapsGroup 7Oxford AQA IGCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWho are they?The halogens: F, Cl, Br, I, AtAll non-metalsDiatomic moleculesExamples: ClX2\ce{Cl2}ClX2, BrX2\ce{Br2}BrX2, IX2\ce{I2}IX2With metalsForm ionic compounds7 electrons in outer shellGain one to form halide ionsHalide ion charge is −1Na+ClX2\ce{Na + Cl2}Na+ClX2 gives NaCl with ClX−\ce{Cl-}ClX−Group 7the halogensFClBrIState and colourFluorine: gas, pale yellowChlorine: gas, pale greenBromine: liquid, red-brownIodine: solid, grey/purple-blackTrends downMelting and boiling points increaseReactivity decreasesFluorine most reactiveIodine least reactiveExam tipsGroup 7 reactivity decreases downGroup 1 is the opposite trendNot every group gets more reactive down