应用化学专业英语第二版万有志主编版课后答案和课文翻译

Unit1TheRootsofChemistryI.Comprehension.2.B3.D4.C5.BII.Makeasentenceoutofeachitembyrearrangingthewordsinbrackets.1.Thepurificationofanorganiccompoundisusuallyamatterofconsiderabledifficulty,anditisnecessarytoemployvariousmethodsforthispurpose.2.Scienceisanever-increasingbodyofaccumulatedandsystematizedknowledgeandisalsoanactivitybywhichknowledgeisgenerated.3.Life,afterall,isonlychemistry,infact,asmallexampleofchemistryobservedonasinglemundaneplanet.4.Peoplearemadeofmolecules;someofthemoleculesinpeoplearerathersimplewhereasothersarehighlycomplex.5.Chemistryiseverpresentinourlivesfrombirthtodeathbecausewithoutchemistrythereisneitherlifenordeath.6.Mathematicsappearstobealmostashumankindandalsopermeatesallaspectsofhumanlife,althoughmanyofusarenotfullyawareofthis.III.Translation.1.(a)chemicalprocess(b)naturalscience(c)thetechniqueofdistillation2.Itistheatomsthatmakeupiron,water,oxygenandthelike/andsoon/andsoforth/andotherwise.3.Chemistryhasaverylonghistory,infact,humanactivityinchemistrygoesbacktoprerecordedtimes/predatingrecordedtimes.4.Accordingto/Fromtheevaporationofwater,peopleknow/realizedthatliquidscanturn/be/changeintogasesundercertainconditions/circumstance/environment.5.Youmustknowthepropertiesofthematerialbeforeyouuseit.IV.Translation化学是三种基础自然科学之一，另外两种是物理和生物。自从宇宙大爆炸以来，化学过程持续进行，甚至地球上生命的出现可能也是化学过程的结果。人们也许认为生命是三步进化的最终结果,第一步非常快,其余两步相当慢。这三步是：（I）物理进化（化学元素的产生），（II）化学进化（分子和生物分子的形成）；和（III）生物进化（有机物的形成和发展）。V.Solution:（1）Therelativemassof1Hand12Catomscanbecalculatedfromtheirabsolutemassesingrams.Ifthemassofa12Catomisexactly12amu,thenthemassofa1Hatomtofivesignificantfiguresmustbeamu.12amux=amu（2）Firstwecalculatekandthenusethefirst-orderrateequation.Thebonewastossedaway(moreprecisely,theanimalwhosebonewasdied)about6100yearsago,orabout4100.Wecanthusbesurethatavillagewasinexistenceatthatplaceatthattime.Unit7TheNomenclatureofInorganicSubstancesI.ComprehensionII.Givethesystematicnameforthefollowingammoniumion;copper(II)ion;strontiumion;Ccopper(I)ion;iron(II)ion;zincion;hydrogenion;lead((II)ion;aluminum;silverion;magnesiumion;chromium(III)ion;Barium;Manganese(II)ion;iron(III)ion;calciumion;mercury(II)ion;chromium(II)ion;tin(II)ion.carbonmonoxide;ditrogentrioxide;carbondioxide;diphosphoruspentoxide;sulfurtrioxide;dichlorineheptoxidearsenateion;sulfiteion;hydrideion;arseniteion;bromideion;hydroxideion;phosphateion;chlorateion;hypochloriteion;phosphateion;chlorideion;iodateion;carbonateion;chloriteion;nitrateion;chromateion;cyanideion;iodideion;dichromateion;fluorideion;nitrateion;oxideion;hydrogencarbonateion;nitriteion;sulfideion;hydrogensulfateion;perchlorateion;sulfateion;hydrogensulfiteion;permanganateion.III.Completethetable. Formula Oldname Systematicname FeO iron(II)oxide Fe2O3 iron(III)oxide Sn(OH)2 tin(II)hydroxide Sn(OH)4 tin(IV)hydroxide Hg2SO4 mercury(I)sulfate HgSO4 mercury(II)sulfate NaCLO sodiumhypochlorite K2Cr2O7 potassiumdichromate Cu3(AsO4)2 copper(II)arsenate Cr(C2H3O2)3 chromium(IV)acetateIV.Acidnamesmaybeobtaineddirectlyfromitsacidionbychangingthenameoftheacidion(negativeion).Usetheruletogivethenameofthefollowingacid. Formulaofacid Oldname Nameofacid H2CO3 carbonicacid HClO2 chlorousacid HClO4 perchloricacid HCN hydrocyanicacid HBr hydrobromicacid H4SiO4 silicicacid H3AsO4 arsenicacidV.Completethesentenceswiththeproperformofthewordgivenattheendofthesentence.altered;illustrateexpectcancel6.arepulledon;referreddiscussedVI.Translation1.Mattercanneitherbecreatednorbedestroyed/eliminated.2.Itisnecessarythatascientistmustknowhowtousefingurestogetanaccutateanswertoquestion.3.Anysubstanceismadeofatomswhetheritissolid,liquidorgas.4.Theexperimentwassuccessful.It’sresultswasthesameaswhatwehadexpected.5.Itwillnotbelongbeforewefinishtheexperiment.VII.Writeequationsforthefollowingacid-basereactions.Usetheinformationininorganictextbooktopredictwhethertheequilibriumwillfavorthereactantsortheproducts.(PartiallySolved)Solutinto(a):CyanideistheconjugatebaseofHCN.Itcanacceptaprotonfromformicacid:Readingfrominorganictextbook,formicacid(pKa=isastrongeracidthanHCN(pKa=,andcyanideisastrongerbasethanformate.Theproducts(weakeracidandbase)arefavored.…………..VIII.Writeequationsforthenetreactionswhichoccurwhenthefollowingmaterialsareaddedtoasodium-ammoniasolution.Answer:(1)2CH3GeH3+2eam-→H2+2CH3GeH2-(2)I2+2eam-→2I-(3)(C2H5)2S+2eam-+NH3→C2H5S-+C2H6+NH2-Unit10NomenclatureofHydrocarbonsI.ComprehensionII.NamethefollowingcompoundsbytheIUPACsystem 1 CH3(CH2)nCH3(n=2,3,4,6,respectively) butane,pentane,hexane,octane 2 (CH3)2-CH2-CH2-CH2-CH3 2-methylpentane 3 (CH3)3C-CH2-CH(C2H5)-CH2-CH3 4-ethyl-2,2-dimethylhexane 4 (CH3)2CH-CH2CH2-CH(CH2CH2CH3)-CH(CH3)2 5-isopropyl-2-methyloctane 5 CH3-CH2-CH2-C(CH2CH2CH3)2-CH(CH3)2 4-isopropyl-4-propylheptane 6 ◇-CH2-CH(CH3)2 isobutylcyclobutane 7 CH2=C(C2H5)(CH(CH3)2) 2-ethyl-3-methyl-1-butene 8 CH3-CH2-CH=CH-CHCl-CH3 2-chloro-3-hexene 9 CH3-CH(CH3)-CH(C2H5)-C≡C-CH3 4-ethyl-5-methyl-2-hexyne 10 CH2=CH-C≡CH 1-buten-3-yne 11 (CH3)2CH-CH2CH(OH)CH3 4-methyl-2-pentanol 12 CH3CH2CH=CHCH(OH)CH3 3-hexen-2-ol 13 (CH3)3C-OH 2-methyl-2-propanol 14 (CH3)3C-OCH2H5 2-ethoxy-2-methylpropane 15 (CH3)2CH-CH2-O-C2H5 1-ethoxy-2-methylpropane 16 (CH2OH)2 1,2-ethanediol 17 CH3-CH(OH)-CH2(OH) 1,2-proanediol 18 CH2(OH)-CH(OH)-CH2(OH) 1,2,3-propanetriol 19 CH3CH2NH2 aminoethane 20 CH3CH2CH2CH(CH3)CH-NH-CH3 N-methyl-1-amino-2-methylpentaneIII.Drawstructuresforthefollowingcompounds. 1 3-octene C-C-C=C-C-C-C-C 2 3-methy-2-heptene 3 cyclohexene 4 2-pentyne C-CC-C-C 5 3,3-dimethylhexyne 6 3-bromotoluene 7 vinylchloride C=C-Cl 8 acetylene CC 9 para-dichlorobenzene 10 m-chlorobromobenzene 11 toluene 12 chlorobenzene 13 1,2-dibromobenzene 14 naphthalene 15 anthracene 16 phenanthrene 17 2-methyl-1-propanol 18 Cyclohexanol 19 Methoxyethene 20 trans-2-ethoxycyclohexanol IV.Decidewhichitembestcompleteseachunfinishedsentence.V.Eachofthefollowingnamesisincorrect.Drawthestructurerepresentedbytheincorrectname(oraconsistentstructureifthenameisambiguous),andgiveyourdrawingthecorrectname.(…………)Unit11CarboxylicAcidsandTheirDerivativesI.ComprehensionII.Fillintheblankswiththephrasesgivenbelow.outorso;puttogethermadeof;dividedbydifferentfromthecontrary;consistofupforas;dependentondownintoIII.Putinproperprepositionsoradverbsintotheblanks.;asIV.Translation1.Similarly,solventalsomaynotbeliquidmatterbuttheothers2.Agraphplottingsolubilityagainsttemperatureiscalledasolubilitycurve.(Thecurveplotdrawn(made/produced)bysolubilityasonecoordinateandtemperatureasanothercoordinateiscalledsolubilitycurve.)3.Airismixtureofgases,themostabundantofwhichisnitrogenintheformofN2(molecules).4.Thedirectionofthereactionandthepositionoftheequilibriummayalsobeaffectedbythetemperature,pressure,andotherconditions.5.Hydrogenhasagreataffinityforoxygenandeasilycombineswithittoformwater.V.Translation玻意尔（Bohr）模型提出不久后，人们就发现原子中的电子比Bohr提出的模型要复杂得多。实验证实电子既有粒子的性质（质量）也有光的特性（波的特性）。因为它的两重性，电子不能被看作是在确定范围内绕核旋转的一种简单粒子，而且如Bohr所说的，如果电子高速运动，我们就不能确切地知道它的位置。Unit13UltravioletandVisibleMolecularSpectroscopyI.ComprehensionII.Fillintheblanksof;as;in;out;In;for;for;of;in;then;to;for;since(for);into.III.Filltheblankineachsentencewithanappropriatephraseinitsproperform.1.accountforpartinof….ascomparedwith5.isattachedtothecontraryinthecaseofcontrastwithasagainst9.owingtofor.Unit17CrystallisationI.ComprehensionII.Fillintheblankswiththeproperwordgivenbelow.Stage;interna;symmetrical;basis;physical;Furthermore;composed;responsible;reasonable;overall.III.Choosetheitemfrom(1)~(6)thatbestmatchestheitemin(a)~(f)tomakeacorrectsentence.1~a;2~b;3~c;4~d;5~e;6~fthefollowingintoChinese共沸物；类质同晶；过饱和；砷酸盐；晶核；异丙基；醇；钠；硫酸盐；间甲酚；糖膏；十水合物；结晶质的；同系物；衍生物；结晶；四硼酸盐；盐析；乙基乙酰苯胺；矿物油。Uint18DistillationI.Comprehension4.AII.Fillintheblankswiththephrasesgivenbelow.ordertorelationto3.inthecaseoftheend5.inanumberoftomessyway掌握以下词汇:flashdistillation闪蒸;exitstream出流;equilibriumcurve平衡曲线;weir堰;redistillation重蒸;apparatus设备;overheadproduct塔顶产物;enthalpy焓;intersection交点;auxiliary辅助装置;rectifyingsection精馏段;reflux回流;reboller再沸器;strippingsection汽提（提馏）段;bottomproduct塔底产物Unit21catalysisI.Comprehension4.BIV.TranslatethefollowingsentencesintoEnglish(1)Wedefineactivityassize(measure)ofcatalysisofcatalyst(2)catalyticreactionmaybecarriedoutindifferentphases,ofwhichmechanismsaregenerallyconsistent(3)Enzymesarethemostefficientproteinsinthehumanbodywhichacceleratethemetabolismofthehumanbody.V.TranslatethefollowingintoEnglishreactionequilibrium;repetitiveness;elementaryreactionstep;stability;catalyticcycle;activity;quantitativeanalysis;selectivity;metabolicreaction;chemicalenergy;reactionmechanism;polymernylon（ornylon）;qualitativeanalysis;molecular-sieve;tubularreactor;inhibitor;stoichiometry.Unit22CosmeticsintroductionI.Comprehension4.D5.(1)True;(2)True;(3)False.II.Fillintheblankswiththeproperwordgivenbelow.Focusedon;considerations;particular;boosting;price;affect;commitment;different;proposed.III.Putinproperprepositionsoradverbsintotheblanks.1.for,of;2.to;3.for4.for(to)5.of,about.V、TranslatethefollowingintoEnglish.对亚苯基二胺，降解，丙烯，头皮屑，洗剂，N-亚硝基二乙醇胺，致癌的，未成熟（or早熟），香波（or洗发剂），激素（荷尔蒙），防汗剂，诱变性，脱臭剂（芳香剂），推论（必然结果），甘油VI、TranslatethefollowingsentencesintoEnglishsurfactant；environmentalpollution；emulsifier；side-effect；dirt；detergent；perspiration；preservative.PARTTWOTHEFUNDATIONSOFCHEMISTRYUnit7ChemicalBonds化学键Thereareapproximately100chemicalelements.世界上大概有100种元素。Therearemillionsofchemicalcompound,andabout600000newcompoundsarepreparedeveryyear.现有数百万种化合物，而且每年有60万种新化合物被合成出来。Toformthesecompounds,atomsofdifferentelementsmustbeheldtogetherinspecificcombinations.beheldtogetherinspecificcombinations以特定的方式为了合成这些化合物，不同种类的原子必须以特定方式结合在一起。Chemicalbondsaretheforcesthatmaintainthesearrangements.That引导定语从句，修饰forces化学键是保持这种结合状态的力。Chemicalbondingalsoplaysaroleindeterminingthestateofmatter.playsarole起作用化学键同时在决定物质状态方面也起作用。Atroomtemperature,waterisaliquid,carbondioxideisagas,andtablesaltisasolidbecauseofdifferencesinchemicalbonding.在室温下，水是液体，二氧化碳是气体，晶体盐是固体，是由于化学键的不同。Asscientistsdevelopedanunderstandingofthenatureofchemicalbonding,theygainedtheabilitytomanipulatethestructureofcompounds.As引导原因状语从句tomanipulatethestructureofcompounds不定式短语做宾补随着化学家对化学键认识的发展，他们获得了控制化合物结构的能力。Dynamite,birthcontrolpills,syntheticfibers,andathousandotherproductswerefashionedinchemicallaboratoriesand()havedramaticallychangedthewaywelive.炸药、避孕药、合成纤维，和数以千计的其他产品在实验室中被合成出来，并且魔术般的改变了我们的生活。Wearenowenteringanerathatpromises(somewouldsayforebodes)evengreaterchange.我们现在进入了一个可望（或者说预言）更大变化的时代。TheDNAmolecular——thechemicalbasisofheredity——carriesitsgeneticmessageinitsbondsinDNA.分子DNA——遗传物质的基础——以它的键传递遗传信息。Whetheranorganismisfish,fowl,hippopotamus,orhumanisdeterminedbythearrangementofbondsinDNA.Whetheranorganismisfish,fowl,hippopotamus,orhuman做主语无论一个生物体是鱼、家禽、河马还是人，都是由于DNA的键的组合方式决定的。Scientistsalreadyhavetheabilitytorearrangethesebonds,andthisabilityhasgiventhemlimitedcontroloverthestructureoflivingmatter.Them,limitedcontroloverthestructureoflivingmatter双宾语科学家已经获得了重组这些键的能力，而这种能力给了他们有限的对生物体结构的控制。Astechniquesofgeneticengineeringimprove,scientistsmayliterallybeabletocustom-tailorgenes.随着基因的发展，科学家们将最终设计出符合条件的基因。Letusbeginourconsiderationofchemicalbondingsothatwe,too,canunderstandtheforcesthatcontrolthestructureofmatter,livingandnonliving.That引导定语从句修饰forces，livingandnonliving，动名词，matter得同位语，修饰matter让我们开始对化学键的论述，并由此理解控制物质，包括有生命体和无生命体，的结构的力。IonicBond离子键Letuslookatanatomoftheelementsodium(Na).我们看一下钠原子。Ithas11electrons,ofwhichtwoareinthefirstenergylevel,eightinthesecond,andoneinthethird.thefirstenergylevel第一能级thesecondenergylevel第二能级thethirdenergylevel第三能级Ithas11electrons,ofwhichtwoareinthefirstenergylevel,eightareinthesecondenergylevel,andoneisinthethirdenergylevel.它有11个电子，其中2个电子在第一能级，8个电子在第二能级，1个电子在第三能级。Ifthesodiumatomcouldgetridofanelectron,thentheproduct,calledasodiumion,wouldhavethesameelectronstructureasanatomofthenoblegasneon(Ne).calledasodiumion分词短语做非限定，修饰productnoblegas如果钠原子能够失去1个电子，产物称为钠离子，就和惰性气体氖（Ne）具有相同的电子结构。Letusimmediatelyemphasizethatthesodiumion(Na+)andneonatom(Ne)arenotidentical.让我们首先强调一下，钠离子（Na＋）和氖原子（Ne）并不相同。Theelectronarrangementisthesame,butthenuclei——andresultingcharges——arenot.electronarrangement电子排布resultingcharges最终电荷电子排布是相同的，而核及最终电荷是不同的。Aslongassodiumkeepsits11protons,itisstillaformofsodium,butitisthesodiumion,notthesodiumatom.只要钠带有11个质子，它就一直是钠，但它是钠离子而不是钠原子。Ionsarechargedparticles,particlesinwhichthenumberofelectronsdoesnotequalthenumberofprotons.inwhich引导非限定定语从句。离子是一种带电粒子，一种电子数不等于质子数的粒子。Positivelychargedionsarecalledcations(pronounced“cat-ions”).Thesodiumionisacation.带正电荷的粒子称为阳离子（音为阳－离子）。钠离子是阳离子。Ifachlorineatom(Cl)couldgainanelectron,itwouldhavethesameelectronstructureasthenoblegasargon(Ar).如果氯原子（Cl）能够得到一个电子，它将与惰性气体氩（Ar）具有相同的电子结构。Thechlorineatom,havinggainedanelectron,becomesnegativelycharged.Ithas17protons(17+)and18electrons(18-).ItiswrittenCl-anditcalledachlorideion.havinggainedanelectron动名词形式做定语，修饰chlorineatom获得一个电子的氯原子带有负电荷。它具有17个质子（17+）和18个电子（18－），写作Cl－，称为氯离子。Negativelychargedionsarecalledanions(pronounced“ann-ions”).Thechlorideionisananion.带负电荷的粒子称为阴离子（音为阴－离子）。钠离子是阴离子。Asodiumformsalessreactivespecies,asodiumion,bylosinganelectron.alessreactivespecies,asodiumion同位语钠原子通过失去一个电子形成不活泼的钠离子。Achlorineatombecomesalessreactivechlorideionbygaininganelectron.氯原子通过得到一个电子形成不活泼的氯原子。Achlorineatomcannotjustpluckanelectronfromemptyspace,norcanasodiumatomkickoutanelectronunlesssomethingelseiswillingtotakeiton.emptyspace空白空间、真空空间，意为“凭空”、“无根据”nor作连词，与助动词和情态动词连用，句中主语与动词倒置。Hecan’tsee,norcouldhehearuntilamonthago.他现在看不见，一个月之前他还听不见。Sheisn’trich,nordoIimagethatsheeverwillbe.她现在不富，我看她将来也富不了。kickout逐出、解雇、开除；意为“失去”Theykickedhimout(oftheclub)forfighting.他因为斗殴而被开除（出俱乐部）。somethingelse别的东西take…on接纳、承受氯原子不能凭空获得一个电子，而钠原子也不能凭空失去一个电子，除非别的东西愿接受电子。WhathappenswhensodiumcomeintocontactwithchlorineTheobvious.Achlorineatomremovesanelectronfromasodiumatom.comeintocontact接触、相遇Theobvious显而易见的当钠与氯接触时发现了什么很明显，氯原子从钠原子处拿走了一个电子。Thesodiumionandthechlorideionhaveelectronarrangements(electronconfigurations)likethoseoftwonoblegases(neonandargon,respectively).electronarrangement电子排布electronconfigurations电子结构钠离子和氯离子的电子排布（电子结构）就象两个惰性气体（氖和氩，相应的）一样。Notonlydotheionshavestableoctetsofelectrons,theyalsohaveoppositecharges.它们具有稳定的电子八耦体结构，而且有相反的电荷。Everyoneknowsthatoppositesattract.每个人都知道异性相吸。Whilethisruleofthumbmaynotalwaysworkwhenappliedtopeople,itworksquitewellforcationsandanions.ruleofthumb单凭经验来做的方法，比较粗糙的方法，约略得衡量（或估计）虽然这种经验对人未必适用，但对阴阳离子是非常适用的。Theattractiveforcebetweenoppositelychargedionsiscalledanionicbond,andthecombinationofsodiumionsandchlorideionsisthecompoundsodiumchlorideortablesalt.相反电荷之间的吸引力称为离子键，钠离子和氯离子结合为化合物氯化钠和食盐。CovalentBonds共价键Onemightexpectahydrogenatom,withitsoneelectron,toacquireanotherelectronandassumetheheliumconfiguration.toacquireanotherelectronand(to)assumetheheliumconfiguration不定式做宾补人们也许希望带有一个电子的氢原子，获得另一个电子并呈现氦的结构。Indeed,hydrogenatomdojustthatinthepresenceofatomsofareactivemetalsuchaslithium,thatis,ametalthatfindsiteasytogiveupanelectron.do代替上句,justthat引导条件状语reactivemetal活泼金属thatis插入语，也就是说ametal，reactivemetal的同位语，that引导定语从句修饰ametal实际上，氢原子只有在活泼金属如锂的存在下确实发生了这样的反应，活泼金属就是很容易失去电子的金属。Butwhatiftherearenootherkindsofatomsaround但是，如果周围没有其他种类的原子呢Whatifthereareonlyhydrogenatoms(asinasampleofthepureelement)如果只有氢原子（作为纯元素样品）呢Onehydrogenatomscanscarcelygrabanelectronsfromanother,foramonghydrogenatomsallhaveequalattractionforelectrons(Evenmoreimportant,perhaps,hydrogenatomsdonothaveatendencytoloseelectronsatall,fortheresultwouldbeahighlyreactivebareproton——thehydrogennucleus.)Evenmoreimportant更重要的一个氢原子几乎不能从另一个氢原子处获取电子，因为氢原子具有相同的电子吸引力（更重要的，可能是，氢原子没有失去电子的倾向，因为那样的结果是生成高度活泼的裸露质子——氢原子核）。Still——hydrogenwantsaduetofelectronslikehelium’s.而且——氢原子希望象氦原子那样拥有2个电子。Ifonehydrogencannotcaptureanother’selectron,thetwoatomscancompromisebysharingtheirelectrons.如果一个氢原子不能获取另一个氢原子的电子，这两个原子则通过共用电子的方式解决。Itisasifthetwohydrogenatoms,inapproachingoneanother,gettheirelectroncloudsororbitalssothoroughlyenmeshedthattheycannoteasilypullthemapartagain.inapproachingoneanother做插入语asif与asthough用法相同，意为：宛如、仿佛、好像。asif后面常用过去时示现在，说明所作的比较“不是真的”。Youlookasifyou’dseenaghost.在非正式文体中，常用like代替asif。Hesattheresmilinglikeitwashisbirthday.就好像两个氢原子，当它们互相接近时，其电子云充分重叠，以至于难于再分开。Moatofthetimetheelectronsarelocatedbetweenthetwonuclei.大部分时间电子位于两个原子之间。Theelectron-dotformulausuallyused,H:H,isthereforeafairlygoodpicture(Ifweweretoattributehumanqualitiestohydrogenatoms,wewouldsuggestthattheyareabitnearsighted.Eachonelooksaround,seestwoelectrons,anddecidesthattheseelectronsareitsveryownandthatthereforeithasasarrangementlikethatofhelium,oneofthenoblegases.)electron-dotformula电子式noblegase惰性气体经常用电子式H：H表示，这是一个很好的画面（如果我们以人的品性归于氢原子，我们说它们有些目光短浅。每个氢原子看看周围，看到两个电子，就认为这些电子是自己的，它们就有了象惰性气体氦那样的电子排布）。Thiscombinationofhydrogenatomsiscalledahydrogenmolecule.这种氢原子化合物叫氢分子。Moleculesarediscretegroupsofatomsheldtogetherbysharedpairsofelectrons.Thebondformedbyasharedpairofelectronsiscalledacovenlentbond.分子是通过共用电子对将两个分离的原子结合在一起。通过共用电子对形成的键称为共价键。Achlorineatomwillpickupanextraelectronfromanythingwillingtogiveoneup.氯原子可以从任何愿意失去一个电子的原子处得到一个电子。But,again,whatiftheonlythingaroundisanotherchlorineatom但是，如果周围只有另一个氯原子又会怎样Chlorineatoms,too,canattainamorestablearrangementbysharingapairofelectrons.氯原子同样也是通过共用电子对达到稳定结构。Eachchlorineatominthechlorinemoleculecountseightelectronsarounditselfandconcludesthatithasanarrangementlikethatofthenoblegasargon.thatithasanarrangementlikethatofthenoblegasargon.宾语从句氯分子中每个氯原子周围都有8个电子，并且可以断定它具有惰性气体氩一样的排布。Thesharedpairofelectronsinthechlorinemoleculealsocreatesacovalentbond.氯分子中共用的一对电子同样形成共价键。Forsimplicity,thehydrogenmoleculeisoftenrepresentedasH2andthechlorinemoleculeasCl2.thechlorinemoleculeasCl2：thechlorinemoleculeisoftenrepresentedasCl2为了简化，氢分子常写成H2，氯分子常写成Cl2。Thesubscriptsindicatetwoatomspermolecule.这个下标表示每个分子中有2个原子。Ineachcase,thecovalentbondbetweentheatomsisunderstood.Sometimesthecovalentbondisindicatedbyadash,H-HandCl-Cl.在每种情况下，原子之间的共价键都可以理解，有时共价键也用一个短线表示H－H和Cl－Cl。：Letusbesureweunderstandthemeaningofnumbersinformulas.让我们确信我们理解公式中数字的意义。Takeamomenttoestablishinyourmindthedifferenceamongthefollowing:H，H2，2H，2H2，H2O，2H2O.花点时间来搞清楚下面数字的不同：H，H2，2H，2H2，H2O，2H2O。IsitcleartoyouthatalthoughHrepresentsasingleatomofhydrogen,H2impliestwoatomsofHbondedtogether,whereas2Hrepresentstwoseparate,free,andindependentatomsofHThat引导实际主语你是否明白H代表分离的氢原子，H2代表两个H结合而成的氢分子，而2H代表分离的、自由的、孤立的氢原子吗Ontheotherhand,themeaningofH2inH2OistotallydifferentfromthatofH2asamolecule.另一方面，H2在H2O中的意思与作为一种分子的H2完全不同。InH2OitmeansthattwoatomsofHareindividuallyattachedtoO（nottothemselves!）toformamoleculeofwater.在H2O中表示两个H分别吸引O（而不是它们自己！）来形成一个水分子。Finally,2H2Osimplyreferstotwoindividualmoleculesofwater.最后，2H2O代表两个独立的水分子。Covalentbondsarenotlimitedtothesharingofonepairofelectrons.Consider,forexample,thenitrogenatom.Itselectron-dotsymbolis：共价键不限于分享一对电子。例如，对于氮原子。它的电子式是：Now,afterallwehavelearnedabouttheoctetruleweknowthatthiselectronarrangementisnotcomplete.octetrule八耦体规则现在，我们学习了八耦体规则。我们知道这个电子排布是不饱和的。Ithasonlyfiveelectronsinitsoutermostenergylevel.outermostenergylevel外层电子能级在它的外层电子能级上只有5个电子。Itcouldsharedapairofelectronswithanothernitrogenatomandwouldthenlooklikethis：它可以与另一个氮原子共用一对电子而变成如下形式：Thesituationhasnotimprovedagreatdeal.情况并没有发生太大变化。Eachnitrogenatominthisarrangementhasonlysixelectronssurroudingit(noteight).每个氮原子周围电子排布只有6个电子（不是8个）。Eachnitrogenatomhastwoelectronshangingouttherewithoutpartners,so,tosolvethedilemma,eachnitrogenatomsharestwoadditionalpairsofelectrons,foratotalofthreepairs.hangingout把…伸出、挂出，上身伸出（窗外），闲荡每个氮原子都有两个未成对电子，所以，为了解决这一矛盾，每个氮原子共用另外两对电子，共3对电子Indrawingthenitrogenmolecule(N2),wehaveplacedalltheelectronsbeingsharedbythetwoatomsinthespacebetweenthetwoatoms.beingsharedbythetwoatoms分词短语做定语写氮分子（N2）时，我们把两个原子的所有的共用电子都写在两个原子中间。Eachnitrogenatomhasnowsatisfiedtheoctetrule.每个氮原子都满足了八耦体规则。Amoleculeinwhichthreepairsofelectrons(atotalofsixindividualelectron)arebeingsharedissaidtocontainatriplebond.inwhichthreepairsofelectrons(atotalofsixindividualele