[理学]c3-group1-alkali-metals

《[理学]c3-group1-alkali-metals》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、Group1elementsAlkalimetals(IA)AssignedreadingmaterialsRayner-DICp245-267;p156-158OptionalreadingmaterialsRayner-DICp253lithiumbatteries;p26511.15biologicalaspectsLiNaKRbCsFrns1Generalizationalkalimetals(ⅠA):ns1锂lithium钠sodium钾potassium铷rubidium铯cesium钫franciumalkalineearthmetals(ⅡA):ns2铍beryll

2、ium镁magnesium钙calcium锶strontium钡barium镭radium原子半径增大金属性、还原性增强电离能、电负性减小原子半径减小金属性、还原性减弱电离能、电负性增大Metallicluster,lowdensity,lowhardness,lowmp.,goodelectricandthermalconductivity.Weakermetallicbond.PropertiesofsimplesubstancesOccurrenceNa:rocksalt(NaCl)seawatersylvinite(KCl/NaCl)borax(Na2[B4O5(OH)4]·

3、8H2O)硼砂Chilesaltpetre(NaNO3)硝石K:sylvite(KCl)seawatersylvinite(KCl/NaCl)carnallite(KCl·MgCl2·6H2O)光卤石Li,Rb,Cs:varioussilicateminerals,e.g.spodumene(LiAlSi2O6)锂辉石Extractionofsodium–DownsprocessExtractionofpotassiumNa(l)+KCl(l)↔K(g)+NaCl(l)At850ºCKb.p.766ºCNab.p.890ºCTheindustrialsynthesisofNaOHTy

4、picalreactionsforalkalimetalsSpeciesofdioxygenspeciesBondorderν(O-O)/cm-1d(O-O)/ÅradicalO2+Dioxygenylcation2.519051.12radicalO2oxygen215801.21biradicalO2-Superoxidedioxide(1-)1.510971.33radicalO22-PeroxideDioxide(2-)18021.49noMolecularorbitalenergyleveldiagramofO22-Whyalkalimetalsformdifferento

5、xides?–AthermodynamicviewpointWhydoalkalimetalsformdifferentoxides?Li2O(LiO0.5)Na2O2(NaO)KO2Thelargealkalimetalcationsstabilizelargelow-chargeanions.Thelesspolarizingcations(thosewithlowchargedensity)stabilizelargerpolarizableanions.Viceversa.TheatypicalpropertyoflithiumLiNaKRbCsχp1.00.90.80.

6、80.8EI1(kJ/mol)520496419403376Eº(M+/M)(V)-3.04-2.71-2.93-2.98-3.03WhyLiisthemostpowerfulreducingmetalamongthealkalimetals?Whichone,LiorNa,reactswithwatermorevigorously?Why?TheatypicalpropertyoflithiumSmallerradiusresultsinhigherhydrationenergyKineticfactorsdeterminethechemicalratesM.p.(Li)=180.

7、54ºCM.p.(Na)=97.81ºC(why)Themeltmetalhaslargersurface.LiOHislesssolubleinwaterthanNaOH.(why)(At288K,5.3vs.26.4mol/L)Themetalcoveredwithhydroxidehassmallerreactionsurface.EachLi+has25.3hydratedwatermolecules;△Hhydration=-519kJ·mol-