ch12---structures-and-properties-of-materials.ppt

New Way Chemistry for Hong Kong A-Level Book 11Chapter 12Structures and Properties of Materials12.1 Classification of Substances According to Structure12.2 Classification of Substances According to the Nature of BondingNew Way Chemistry for Hong Kong A-Level Book 12Some Pre-knowledgesolidParticles(may be molecules,ions or metallic atoms)forces of attraction between particles weakenliquidgasforces of attraction between particles broken12.1 Classification of Substances According to Structures(SB p.277)New Way Chemistry for Hong Kong A-Level Book 1312.1 Classification of Substances According to Structures(SB p.278)New Way Chemistry for Hong Kong A-Level Book 14Simple Molecular StructuresExamplesforces of attraction between particles weaken(by raising the temp.)forces of attraction between particles broken(by further raising the temp.)solid iodine(at room temp.)liquid iodineGaseous iodine12.2 Classification of Substances According to the Nature of Bonding(SB p.279)New Way Chemistry for Hong Kong A-Level Book 15Simple Molecular StructuresExamplessolid chlorine(at room temp.)liquid chlorinegaseous chlorine(at room temp.)forces of attraction between particles strengthen(by lowering the temp.)(by further lowering the temp.)forces of attraction between particles weaken12.2 Classification of Substances According to the Nature of Bonding(SB p.279)New Way Chemistry for Hong Kong A-Level Book 1612.2 Classification of Substances According to the Nature of Bonding(SB p.280)Properties of simple molecular substances1.Low melting points and boiling points2.Soft and easily distorted3.Non-conductors of electricity4.Usually insoluble in oplar solvents but soluble in non-polar solventsNew Way Chemistry for Hong Kong A-Level Book 17Macromolecular StructuresSubstances with macromolecular structures consist of very large molecules containing thousands of atoms.12.2 Classification of Substances According to the Nature of Bonding(SB p.281)New Way Chemistry for Hong Kong A-Level Book 18Giant StructuresSubstances with giant covalent structure(graphite),giant ionic structure(sodium chloride)and giant metallic structure (copper)Graphite(giant covalent structure)12.2 Classification of Substances According to the Nature of Bonding(SB p.280)New Way Chemistry for Hong Kong A-Level Book 19Giant covalent structuresdiamond and silicon(IV)oxide(quartz)12.2 Classification of Substances According to the Nature of Bonding(SB p.279)New Way Chemistry for Hong Kong A-Level Book 110Giant covalent structuresThe giant covalent structures of graphite(a layered structure)12.2 Classification of Substances According to the Nature of Bonding(SB p.279)New Way Chemistry for Hong Kong A-Level Book 11112.2 Classification of Substances According to the Nature of Bonding(SB p.281)Properties of giant covalent substances1.High melting points and boiling points2.Hard and rigid3.Poor conductors of heat and electricity4.Insoluble in any solventNew Way Chemistry for Hong Kong A-Level Book 11212.2 Classification of Substances According to the Nature of Bonding(SB p.281)Properties of ionic compounds1.High melting and boiling points2.Hard but brittle3.Good conductors of electricity in molten or aqueous state4.Soluble in polar solvents but insoluble in non-polar solventsNew Way Chemistry for Hong Kong A-Level Book 11312.2 Classification of Substances According to the Nature of Bonding(SB p.283)Properties of metals1.High melting and boiling points2.Good conductors of heat and electricity3.High density4.Malleable and ductileNew Way Chemistry for Hong Kong A-Level Book 114