IGCSE›Edexcel IGCSE Chemistry›Mind maps2.1 Group 1 (Alkali Metals)Edexcel IGCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWhy a group?1 electron in the outer shellLose it to form 1+ ionsSimilar reactions show one familyWith waterMetal hydroxide + hydrogen2 Na+2 HX2O→2 NaOH+HX2\ce{2Na + 2H2O -> 2NaOH + H2}2Na+2HX2O2NaOH+HX2Float, move about, fizz and dissolveSolution is alkaline: universal indicator purpleReactivity trendLi gentle, Na faster, K violentPotassium burns with a lilac flameTarnish faster down the groupK stored under oilGroup 1the alkali metalsLiNaKRbCsPredictionsRb and Cs react more vigorously than KLower melting points down the groupStill form hydroxide + hydrogenWhy more reactive?More shells down the groupOuter electron further from nucleusMore shielding by inner shellsWeaker attraction → easier to loseExam tipsSay potassium reacts violently, not explodesExplanation needs shells, distance and shieldingMissing one link loses marks