GCSE›AQA GCSE Chemistry›Mind mapsAtoms, Elements and CompoundsAQA GCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWhat is an atom?Smallest part of an element that can existEverything is made of atomsEach element has a chemical symbolLearn the first 20 elements plus Groups 1 and 7Three kindsElement: only one type of atomCompound: elements chemically combinedMixture: not chemically combinedCompounds split only by a chemical reactionAtomselements and compoundsNaClOMgFormulaeFormula shows elements and the ratio of atomsNaCl\ce{NaCl}NaCl is sodium chlorideCOX2\ce{CO2}COX2 is carbon dioxide2 Mg+OX2→2 MgO\ce{2Mg + O2 -> 2MgO}2Mg+OX22MgOSeparating mixturesFiltration: insoluble solid from liquidCrystallisation: soluble solid from solutionSimple distillation: solvent from solutionFractional distillation: liquids with different boiling pointsChromatography: stationary vs mobile phaseExam tipsSymbols: capital first, then lower caseCo is cobalt but CO is carbon monoxideIron and sulfur mixture: magnet worksIron sulfide compound: magnet fails