AQA GCSE Chemistry - Atomic Structure and the Periodic Table PDF

AQA​ ​GCSE​ ​Chemistry Topic​ ​1:​ ​Atomic​ ​Structure​ ​and​ ​the Periodic​ ​Table The​ ​Periodic​ ​Table Notes (Content​ ​in​ ​bold​ ​is​ ​for​ ​Higher​ ​Tier​ ​only) www.pmt.education The​ ​periodic​ ​table...

AQA​ ​GCSE​ ​Chemistry Topic​ ​1:​ ​Atomic​ ​Structure​ ​and​ ​the Periodic​ ​Table The​ ​Periodic​ ​Table Notes (Content​ ​in​ ​bold​ ​is​ ​for​ ​Higher​ ​Tier​ ​only) www.pmt.education The​ ​periodic​ ​table Elements​ ​are​ ​arranged​ ​in​ ​order​ ​of​ ​atomic​ ​(proton)​ ​number​ ​(smaller​ ​number)​ ​and​ ​so that​ ​elements​ ​with​ ​similar​ ​properties​ ​are​ ​in​ ​columns,​ ​known​ ​as​ ​groups. Elements​ ​in​ ​the​ ​same​ ​periodic​ ​group​ ​have​ ​the​ ​same​ ​amount​ ​of​ ​electrons​ ​in​ ​their outer​ ​shell,​ ​which​ ​gives​ ​them​ ​similar​ ​chemical​ ​properties. The​ ​early​ ​periodic​ ​table John​ ​Newlands Dmitri​ ​Mendeleev Ordered his table in order of atomic Ordered​ ​his​ ​table​ ​in​ ​order​ ​of​ ​atomic weight mass,​ ​but​ ​not​ ​always​ ​strictly​ ​–​ ​i.e.​ ​in Realised similar properties occurred some​ ​places​ ​he​ ​changed​ ​the​ ​order every eighth element – ‘law of based​ ​on​ ​atomic​ ​weights. octaves’ but broke down after Left​ ​gaps​ ​for​ ​elements​ ​that​ ​he calcium. thought​ ​had​ ​not​ ​been​ ​discovered yet. The​ ​table​ ​is​ ​called​ ​a​ ​periodic​ ​table​ ​because​ ​similar​ ​properties​ ​occur​ ​at​ ​regular intervals. Elements​ ​with​ ​similar​ ​properties​ ​are​ ​found​ ​in​ ​the​ ​same​ ​column​ ​(groups) The​ ​modern​ ​periodic​ ​table Elements​ ​with​ ​properties​ ​predicted​ ​by Mendeleev​ ​were​ ​discovered​ ​and​ ​filled​ ​the gaps. o Knowledge​ ​of​ ​isotopes​ ​made​ ​it​ ​possible to​ ​explain​ ​why​ ​the​ ​order​ ​based​ ​on atomic​ ​weights​ ​was​ ​not​ ​always​ ​correct. When​ ​electrons,​ ​protons​ ​and​ ​neutrons​ ​were discovered​ ​in​ ​the​ ​early​ ​20​th​​ ​century,​ ​elements were​ ​ordered​ ​in​ ​atomic​ ​(proton)​ ​number. When​ ​this​ ​was​ ​done,​ ​all​ ​elements​ ​were​ ​placed​ ​in​ ​appropriate​ ​groups. Metals​ ​and​ ​non-metals Metals​ ​=​ ​elements​ ​that​ ​react​ ​to​ ​form​ ​positive​ ​ions. o Majority​ ​of​ ​elements​ ​are​ ​metals. o Found​ ​to​ ​the​ ​left​ ​and​ ​towards​ ​the​ ​bottom​ ​of​ ​the​ ​periodic​ ​table. Non-metals​ ​=​ ​elements​ ​that​ ​do​ ​not​ ​form​ ​positive​ ​ions. o Found​ ​towards​ ​the​ ​right​ ​and​ ​top​ ​of​ ​the​ ​periodic​ ​table. Group​ ​1​ ​–​ ​Alkali​ ​metals They​ ​have​ ​characteristic​ ​properties​ ​due​ ​to​ ​the​ ​single​ ​electron​ ​in​ ​their​ ​outer​ ​shell. Metals​ ​in​ ​group​ ​one​ ​react​ ​vigorously​ ​with​ ​water​ ​to​ ​create​ ​an​ ​alkaline​ ​solution​ ​and hydrogen. They​ ​all​ ​react​ ​with​ ​oxygen​ ​to​ ​create​ ​an​ ​oxide. They​ ​all​ ​react​ ​with​ ​chlorine​ ​to​ ​form​ ​a​ ​white​ ​precipitate. The​ ​reactivity​ ​of​ ​the​ ​elements​ ​increases​ ​going​ ​down​ ​the​ ​group: www.pmt.education  reaction​ ​with​ ​oxygen reaction​ ​with​ ​water reaction​ ​with​ ​chlorine lithium burns​ ​with​ ​a​ ​strongly Fizzes​ ​steadily,​ ​gradually white​ ​powder​ ​is​ ​produced red-tinged​ ​flame​ ​and disappears and​ ​settles​ ​on​ ​the​ ​sides​ ​of produces​ ​a​ ​white​ ​solid the​ ​container sodium strong​ ​orange​ ​flame​ ​and Fizzes​ ​rapidly,​ ​melts​ ​into​ ​a burns​ ​with​ ​a​ ​bright​ ​yellow produces​ ​white​ ​solid ball​ ​and​ ​disappears​ ​quickly flame,​ ​clouds​ ​of​ ​white powder​ ​are​ ​produced​ ​and settle​ ​on​ ​the​ ​sides​ ​of​ ​the container potassium large​ ​pieces​ ​produce​ ​lilac Ignites​ ​with​ ​sparks​ ​and​ ​a reaction​ ​is​ ​even​ ​more flame,​ ​smaller​ ​ones​ ​make lilac​ ​flame,​ ​disappears​ ​very vigorous​ ​than​ ​with​ ​sodium solid​ ​immediately quickly Group​ ​0​ ​–​ ​Noble​ ​gases They​ ​have​ ​8​ ​electrons​ ​in​ ​their​ ​outer​ ​shell​ ​(except helium,​ ​which​ ​has​ ​2).​ ​All​ ​of​ ​them​ ​(including​ ​helium) have​ ​full​ ​outer​ ​shells They​ ​are​ ​unreactive​ ​and​ ​do​ ​not​ ​easily​ ​form​ ​molecules, because​ ​they​ ​have​ ​a​ ​stable​ ​arrangement​ ​of​ ​electrons (full​ ​outer​ ​shell). The​ ​boiling​ ​points​ ​of​ ​the​ ​noble​ ​gases​ ​increase​ ​with​ ​increasing​ ​relative​ ​atomic​ ​mass (going​ ​down​ ​the​ ​group). Group​ ​7​ ​–​ ​The​ ​halogens Similar​ ​reactions​ ​due​ ​to​ ​their​ ​seven​ ​electrons​ ​in​ ​their​ ​outer​ ​shell. Non-metals​ ​and​ ​exist​ ​as​ ​molecules​ ​made​ ​of​ ​pairs​ ​of​ ​atoms​ ​(e.g.​ ​Cl​2​) They​ ​react​ ​with​ ​metals​ ​to​ ​form​ ​ionic​ ​compounds​ ​in​ ​which​ ​the​ ​halide​ ​ion​ ​carries​ ​a​ ​-1 charge. they​ ​react​ ​with​ ​nonmetals​ ​to​ ​form​ ​covalent​ ​compounds,​ ​where​ ​there​ ​is​ ​a​ ​shared​ ​pair of​ ​electrons as​ ​you​ ​go​ ​down​ ​the​ ​group,​ ​relative​ ​molecular​ ​mass,​ ​melting​ ​point​ ​and​ ​boiling​ ​point all​ ​increase reactivity​ ​decreases​ ​down​ ​the​ ​group​ ​because: o halogens​ ​react​ ​by​ ​gaining​ ​an​ ​electron​ ​(to​ ​increase​ ​their​ ​number​ ​of​ ​outer​ ​shell electrons​ ​from​ ​7​ ​to​ ​8) o the​ ​number​ ​of​ ​shells​ ​of​ ​electrons​ ​increases​ ​down​ ​the​ ​group,​ ​so​ ​down​ ​the group​ ​the​ ​element​ ​attracts​ ​electrons​ ​from​ ​other​ ​atoms​ ​less,​ ​so​ ​can’t​ ​react​ ​as easily decrease​ ​in​ ​reactivity​ ​means​ ​that​ ​a​ ​more​ ​reactive​ ​halogen​ ​(one​ ​from​ ​higher​ ​up​ ​group 7)​ ​can​ ​displace​ ​a​ ​less​ ​reactive​ ​one​ ​in​ ​an​ ​aqueous​ ​solution​ ​of​ ​its​ ​salt. ▪ E.g.​ ​Chlorine​ ​will​ ​displace​ ​bromine​ ​if​ ​we​ ​bubble​ ​the​ ​gas​ ​through​ ​a solution​ ​of​ ​potassium​ ​bromide: ▪ Chlorine​ ​+​ ​Potassium​ ​Bromide​ ​→​ ​Potassium​ ​Chloride​ ​+​ ​Bromine www.pmt.education