GCSE›AQA GCSE Chemistry›Mind mapsCovalent Bonding and Simple Molecular SubstancesAQA GCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsThree bondsIonic: transfer of electronsCovalent: sharing pairs of electronsMetallic: delocalised electrons sharedSharingAtoms share pairs for a fuller outer shellShown by dot and cross diagramsSingle bond drawn as a line, H–HIn HX2\ce{H2}HX2 each atom gets two outer electronsCovalent bondssimple moleculesH2O2H2OCH4Simple moleculesSmall molecules: HX2\ce{H2}HX2, ClX2\ce{Cl2}ClX2, HX2O\ce{H2O}HX2O, COX2\ce{CO2}COX2Strong covalent bonds within moleculesWeak intermolecular forces between themPropertiesLow melting and boiling pointsOften gases or liquids at room temperatureLarger molecules: higher melting pointDo not conduct: no free ions or electronsExam tipsMelting breaks intermolecular forcesCovalent bonds inside molecules stay intactLarger molecule means stronger forces