the following content isprovided under a creative commons license. your support will help mitopencourseware continue to offer high-quality educationalresources for free. to make a donation or viewadditional materials from hundreds of mit courses, visitmit opencourseware at ocw.mit.edu. professor: let's get started. settle down.
welcome to 3.091. i'm donald sadoway and i'm goingto be your instructor this semester. so what i want to do todayis to introduce my plans. i've got plans for you. plans for learning. i want to talk a little bittoday about those plans, introduce myself, introducemy class curriculum-- the path forward.
so let me begin by saying that3.091 is the most important class you will take at mit. it's true. but, you know, anybody whostands in front of you to lecture should say the samething about his or her class. if they don't believe that theyshouldn't be standing in front of you lecturing. the difference is wheni say it, i'm right. [laughter]
professor: and it's not justan opinion, it's because of the content of 3.091. 3.091 is about chemistry. it's about the central science,but it's not just about any old chemistry. this isn't a class that youcould take anywhere else in this country. this is the only place thatyou can take 3.091. 3.091 is solid statechemistry.
now why do we talk aboutsolid state chemistry? because engineering systemsare made of solids. now i know what you'rethinking-- oh, he said solid state, he's going to talkabout the chemistry that constitutes his laptop computeror the chemistry that constitutes thislaser pointer. and that's true. we will talk aboutthat chemistry. but we will also talkabout soft matter.
we as human beings arechemical machines. when this hand changes shape,it is a polymer that is changing conformality. these eyes are photodetectors,band gap of about two electron volts. they're not made ofgallium nitride. they're made of organiccompounds. inside, what supports us,it's a ceramic skeleton. so solid state chemistrydescribes
life science as well. well, what we're goingto learn in 3.091 is the rudiments. we're going to learnthe rudiments. so what i'm going to do today isnow go through some of the basic organization. so tomorrow you're goingto meet your recitation instructors and get to know eachother and get to know the recitation instructor.
today i'll say a few words aboutmyself so you know who's standing in front of you. i graduated from the universityof toronto in chemical metallurgy, came downhere in 1977 to spend a year as a postdoctoral fellow and, iguess, i lost track of time. now what's my research? my research is inelectrochemistry. electrochemistry is the mostimportant branch of chemistry. do you notice some theme inmy professional life?
see, i have tenure. so what does that mean? it means you find your passionand pursue it. you don't waste time ontrivia, all right? and that's what i urgeyou to do: find your passion and pursue it. so what's my passion? my passion is electrochemistryin nonaqueous media. anything but water.
let the rest of the worldwork on water. i work on molten salts, ionicliquids, and polymers. and what's the reasonfor this? there's an application. i'm in the schoolof engineering. so i'm interested inenvironmentally sound technologies for metalproduction, all right? right now looking at titanium,iron recycling as well. i'm also interested inelectrochemistry as it applies
to energy storage, energystorage for mobile power. see this gal here? she's got the cell phone. she's not even lookingwhere she's driving. professor: so making safebatteries out of earth-abundant, accessiblematerials for portable power, ultimately to drive the car withelectrons, electric fuel, to eliminate this country's dependence on imported petroleum.
we can do it. how? by inventing. and the way we're going toinvent is to learn the lessons in 3.091 that will give us thechemistry we need to invent a battery that can send that car250 miles on a single charge, and put it in a show room forthe same price as a car with an internal combustion engine. the only thing that standsbetween that image and where
we are today is invention, andthe requisite material is right here in this class. we're also looking atcolossal batteries. store the grid. enable renewables,wind, solar. and then, lastly, let's neverforget about dreaming. so if we want to dream andimagine that man will return to the moon or maybe even go tomars, we're going to have to be able to produce oxygen.
we'll live like the pioneers,produce oxygen from local resources, produce structuralmetals, and even produce photovoltaic silicon so they cangenerate their own energy from local resources. and so electrochemistry is thekey enabler for that as well. so now let's turn to the wholeunderpinning of 3.091. if we take a look at theperformance of any engineering system it's a combinationof the design and the construction.
now the construction is both theworkmanship and the choice of materials. now how do we choosematerials? we choose them on the basisof their properties. so, for example, here's an application: a beverage container. this one i'm holding is madeout of an aluminum alloy. it's a metal. when i was your age, theyhad steel beverage cans.
you can take this same beverageand contain it in a glass bottle. you can contain it ina polymer bottle. why do we make thosevarious choices? because they have the rightmix of properties. now how do you determinethe properties? properties obviously aredetermined by the composition. we wouldn't make this thingout of sodium chloride. it would dissolve.
so composition is important,but atomic arrangement is important as well. example is 1/2-inch-thickpine board compared to a 1/2-inch-thick pieceof plywood. both pine, but the1/2-inch-thick pine board is one solid pine board. i can take that pine board andi can fracture it if i strike it along the grain. but the 1/2-inch-thick plywood,i can't do that
because it's 1/8-inch sheetpine cross-laminated. 1/8 inch north-south, 1/8 incheast-west. if i try to cut through that board, i can'tadvance the fracture. same composition, differentatomic arrangement. so the thesis of 3.091 is thatthe electronic structure of the elements holds the keyto understanding that relationship betweencomposition, atomic arrangement, and properties. and once you have propertiesthat's how
you make your selection. and away we go. and that's how we got thesyllabus of 3.091. so the syllabus hastwo major blocks. the first block is generalprinciples of chemistry-- it's going to be about thefirst five weeks-- and that's the same stuff thatyou get here, 5.111, 5.112, the basics of electronicstructure and bonding. and then we part company andin 3.091 we dig down into
solid state chemistry. you don't have to take notes. you can relax. all this is going to beburned to pdf and posted at the website. so everything that you see inthis class that goes up on the screen is archived for you. this lecture is being videorecorded right now and within an hour will be postedat the website.
so in the unlikely event thatyou can't quite come to class, it is available. professor: so now what i want todo is introduce some of the operational aspectsof the class. and we had some handoutsgoing around. if you didn't get them wecan get you extras. but again, this is all postedat the website. so you know who i am. the key person in this operationis my administrative
assistant, hilary sheldon, andshe's just down the hall. you can roll a penny downthe hall from here and get to my office. so if you tell me you triedlooking for me, you couldn't find me, i know you couldn'thave been trying very hard. the text is a two-volume setconsisting of the text chemistry: principles, patterns,and applications by averill and eldredge, and thena second volume that consists of miscellaneous readingstaken from other
prentice hall texts. and it's identical in content tothe blue book that was used last year and the year before. so if you get a copy ofthat blue book, you don't have to buy these. i don't work for prentice hall,i'm not trying to sell books, but we will take thehomeworks out of the books to a great extent. and the page numbering is thesame, so anything this year or
the last two yearswill be fine. if you have to buy something,you'll have this. this one will come with a cdthat will get you into a mastering chemistry, whichis a sort of a tutorial, computerized system to helpyou with certain homework problems. the lectures, monday, wednesday,friday, here in this room at 11 o'clock. the lecture starts at fiveminutes after the hour--
gives you five minutesto get in-- and then the lecturestops at five minutes to the next hour-- time for you to leave and thenfor the next class to arrive. and what i'm going to tryto do is establish some plug flow here. so what i'm going to try is tohave everybody leave by the exit to the north here to myright, and there's also an exit over the top back.
so leave to your left and thatway it'll be easier for the next class to come in. and maybe we can persuade thepeople here before us to do the same and then it'llbe easy to change. i don't know why but there'sthis sort of-- everybody has to charge to this door. and i just stand here andwatch people collide. and i don't know. just interesting socialexperiment.
and there are two doors. i don't understand why peopledo this, but i'm not in the social sciences. recitations. recitations will meet tuesdaysand thursdays. so you'll go to the same houron tuesday and thursday. the section should beroughly 20 students. and that's where the questionand answer occurs. here it's largely italk, you listen.
i've got time for a questionlike, hey, shouldn't that be a minus sign? i can take somethingreally quick. but where you get to reallyinteract with the instructor is in recitation. and i've given a direction to myrecitation instructors not to give you a fourthand fifth lecture. you control the contentof the recitation. so you have to cometo the recitation
prepared with questions. so they're supposed to walk inand say, good morning, good afternoon, what areyour questions? and you can say, i didn'tunderstand the last five minutes of the lectureyesterday. would you do number fiveon the homework? would you go over secondarybonding? that's the sort of thingthat's supposed to happen in section.
you've been assignedby the registrar. you are forbidden to changeyour section on your own. you can't just squatin another section. we do this with the intentionof trying to keep the enrollment roughly uniform. we don't want sections growingto 35 because then that limits your ability to interact. if you've changed classes oryou've picked up a urop, or what have you, and yoursituation has changed, please
go down the hall and meet withmy assistant hilary, who will then arrange to move you. and that way we can keep somecontrol over the section size. again, you may not changesimply on your own. and it has to be with cause,academic cause. you can't go in and say, i wasassigned to the 9:00 am section and i don'tdo mornings. that's not going to work. homework.
homework is veryimportant here. homework is a little bitdifferent, though, in 3.091. you're not going to beasked to turn in homework for grading. instead, at the beginning ofeach unit, you will be given homework with themodel solutions right at the beginning. this is a study aid, and you canuse the model solutions to help you understand thehomework material.
now since we're not asking youto turn anything in and we do want to stimulate interest inthe homework, we found a way to stimulate interest. and thatis that once a week in section you will havea 10-minute quiz based on the homework. that will ensure thatyou've at least looked at the homework. and those weekly quizzes willbe graded, and the aggregate of all of those quiz scores willconstitute your homework
grade in the subject. and you must takethose quizzes. if you don't take the quiz-- you got sick or some personalemergency came up-- contact your recitation instructor andwithin a week of the date of the original quiz arrangeto take a makeup. if you don't take themakeup, we're going to give you a zero. and there's no droppingof lowest score.
somewhere there's this in thelore here that, oh, you can drop the lowest score, thelowest two scores. people come to me with thisproposal and i say no. professor: so let'sget started. this is homework number one. it's assigned today. we're going to save paper--just go to the website-- and you'll be tested ontuesday, next tuesday, september 15, at the beginningof section.
at the beginning of sectionthere'll be a 10-minute quiz based on that homework,and you can get the homework and so on. by the way, here's what thehomework looks like. chapter 1, chapter3 of averill. averill is the major text. we just refer to it by theauthor's last name. so taken from averill. by the way, i don't like touse this unpleasant term
"test." i like to refer to it asa celebration of learning. professor: so it'sa celebration. we're going to start celebratingon tuesday. there's the websiteby the way. you probably want tobookmark that. you're probably goingto go to that a lot. we're going to keep celebrating,and so we will have some monthly celebrations,monthly tests, and they've alreadybeen scheduled.
and you will write those testsduring the normal class time. but on those days we willspread you out a bit. i like to see some vacancies. so you will not be sittingone next to another. there'll be at least one humanvacancy next to every human, and that way you've got room tospread out, keep your eyes on your own work. so those are the datesand there'll be more of that in time.
now when you take the monthlytest, i allow you to use aids. so everyone will be given inrecitation tomorrow a periodic table of the elements, verynice one, laminated one. so you take that with you to thetest. in fact, you should take this with you everywhere. professor: if i run into you atharvard square, i want to see the periodic table, becauseevery educated person has the periodic table. you get a table of constants.
so you'll have one of these. you'll get that tomorrowas well. paper copy, and on there are allthe constants so you don't have to remember that thepermittivity of vacuum is 8.85 times 10 to the minus12 farads per meter. it's on there. i urge you to use that whenyou do your homework. so it's always amusing to meduring the time of the first monthly celebration, somebody'slooking at this as
though it's today's newspaperand they're looking, where is that? sort of revealing about theintensity with which the homework has been embraced. calculator, something tocalculate with, and i don't care if you bring in a graphing calculator or a mainframe. i don't care. professor: and you're allowedan aid sheet, an 8 1/2-by-11
sheet of paper. and you can write onthe front, you can write on the back. you can photoreduce previousexams down to micro-dot size. i don't care what you put onit, but with this, you have then no excuse to say i reallyunderstood this stuff, but i couldn't remember a formula. actually, many students tell methat the act of preparing the aid sheet organizes thesubject matter in their minds.
they bring this with them tothe exam, and they never consult it, but it just soothesthe nerves and makes sure that everybody does wellon the monthly test. the weekly test, no. the weekly test you bring yourperiodic table and table of constants, but no aid sheet. for the weekly test,it's a very concentrated amount of material. and i'm not going to test yourmemories, because that doesn't
prove anything to me. and then, of course, thecelebration of celebrations is the final exam. professor: that's huge. that's a huge celebration. it's three hours. see, these are really50 minutes. this is three full hours. the time and location willbe set by the registrar.
we should know by october 1. the final exam period isdecember 14 to 18. and so what i urge you to dois as soon as that schedule comes out and we know when allthe final exams are going to be held, then you book yourpassage for the holidays. do not get that orderreversed. you cannot come to me andsay, i got a really good price on a ticket. i'm going acapulco on the 15thof december, and your exam is
on the 16th of december. i'll say, you just gota zero on the final. you have to be here for that. you know why? i have to be here for that, youcan be here for that, too. there are about a quarter of amillion students in boston. it's a great college town, butat christmas time, it's pandemonium at logan airport. so you want to book your passageearly, but you can't
do it until you know what yourfinal exam obligations are. grading. freshman, you know, it'spass/no record. pass/no record. and so that means that if youstruggle and things don't go well, you don't have anyblemishes on your record. unfortunately, some of theupperclassmen will tell you as pass/no record, younow, barest pass imaginable/ no record.
well, i hate to let you knowthis, but increasingly i am being asked by medicalschools, law schools, scholarship providers to revealthe scores on the freshman year. so think about that before youcall hilary in late november saying, what do i needto get a 50? i need a 32 on the final? ok. but lord help you, youget a 31 you go down.
professor: upperclassmen getthe luxury of the entire alphabet: a, b, c, d, f. the final grade composition. 1/6 for homework-- that's the aggregates of theweekly test scores-- and 1/6 for each of the three tests. and then the finalis 2/6, or 1/3. i didn't want to get intotranscendental numbers, so i made it 33 exact, 16.75 exact.
i could have made it 16.77, icould have made it 16.81, i could have made itanything i want. i'm the professor. but i chose 16.75. bottom line here is it's reallydumb to fail the final. if you passed the final, you'repretty much assured that we're goingto be favorably disposed to passing you. but you fail the finalthat says two things.
it says, number one, you don'thave a grasp of the overall year, but it also sort ofindicates that you ran out of steam partway through thesemester and stopped working. it's very bad. you get a lot of good advicefrom upperclassmen, but sometimes-- i'd ignore that one that says,hey, you don't have to do that well on the final. anyway, so you have toget a c level as
a freshmen or greater. and, by the way, we donot grade on a curve. i've seen it in magazinesthis last year that mit grades on a curve. i don't where theyget that from. i don't grade on a curve. your success does not come atthe expense of your neighbor. as far as i'm concernedeverybody in this class can get an a.
again, i'm the professor,all right? so you say, well, howdo you know that 50 is the right number? why isn't it 55? why isn't it 75? well, i know. i know. how do i know? because when we grade, we set upthe point scheme so that if
the student has the mastery ofthe barest level of competency of the key concept thepoint scheme must reflect a passing grade-- 5 out of 10, 5 out of 9-- and you propagatethat through. i don't care how much iswritten, if it doesn't demonstrate basic mastery ofthe key concept the point scheme must give 4, 3, 2, 0. maybe a 1.
and so that, if you propagate itthrough the whole semester, means 50 is a pass. there's some wiggleroom there. how do i know 49.7 is afail and 50 is a pass? that's when i call yourrecitation instructor. [cell phone ringing] professor: let's kill that. we're going to get tothat in a second. let's call the recitationinstructor.
and what happens? i ask the recitation instructor,well, what can you tell me about this young lady? and, oh, she came to all myclasses, she tried really hard, she came tooffice hours. i don't think the exam is aproper reflection of her understanding. i'll listen to that andmaybe we'll promote. if, on the other hand, i get theresponse, i never saw her,
didn't come to class. i repeatedly reached out to her,ignored my entreaties, she's going down. professor: ok. website. this is what the websitelooks like. there's a number of tabs here. the readings are there, thevideos are there archived. the schedule--
what's going to be coming up. so, for example, this iswhat's going on today. it says what the topic is,roughly what the readings are. i know today you didn't cometo class having read. and it's ok, we'llget through it. but from now on i urge youto do the readings. a couple of topics i'm requiredto talk about. my management requiresme to do so. academic honesty.
there's a lot of texts here,but in plain english, this says don't cheat! you know what this means! now i don't want to hear,well, in my country, the custom is-- i don't care what theydo in your country! you're in my class, and ifyou cheat in my class you will pay for it. very simple.
accept information of anykind from others-- wrong. represent somebody else's workas your own-- wrong. you know this. it was juvenal, the romanpolitician, said men need not so much be instructedas reminded. i'm not telling you anythingyou don't already know, but i'm going to say it so no onecan say, well, nobody told us it wasn't ok to erase ouranswers and hand them back in
for more points. i just did. all right? so if in the unlikely-- butit happens every so often. maybe every two, three years. and people get caught. you know why they get caught? because for the first time inyour life you're being taught by people who are assmart as you are.
professor: my tas arereally smart. and it never ceases to amazeme-- somebody succumbs and does something dishonest,and they get caught! they get busted! and what happens then? then i get angry. because we can't settlethat in my office. you can't come andcry in my office. i have to take this episode to acommittee here at mit called
the committee on discipline. it is staffed by faculty, by administrators, and by students. and the case is brought beforethe cod at a hearing and a punishment is decided. and it can be anything fromsuspension to expulsion. and of the three categories,faculty, administrators, students, which category do youthink is most severe on infringers?
audience: students. professor: your peers. you got it. you know, because people my age,old faculty, they'll be like, oh, they're justkids, whatever. the students say, no! throw them out! professor: so it's not going tobe me that's going to expel you, it's going tobe your peers.
so don't do it. and if you're ever in an examand somebody's pressuring you, just raise your hand andask to be reseated. for all i know, the guy next toyou has got a bad case of b.o., you just want to move. we will not ask anyquestions, so take yourself out of the situation. conduct yourselfappropriately. classroom behavior.
now this is the first lecture,there's a whole bunch of violations in here right now. so i'm going to say it now andwe'll fix it for next time. we've got 425 seats here, we'veprobably got 475 people, and there's only one way we canmake this system work and we have to observe certainrules of decorum. and i make the rules. so if i want to maintain afertile learning environment i'm going to ask for theserules to be observed.
no talking at all. no talking. little conversation here, littleconversation here-- it disturbs people. i don't want anyfood or drink. no food, no drink. one exception isthe professor. professor: because i do not wantto have my throat get so dry that i can't finish talkingmy way through the end
of the class. otherwise, no food or drink andno disruptive behavior. no horseplay or anythinglike that. and wireless communicationdevices must be silenced. cell phone goes off, you getup, you leave the room. that's it. audience: is water ok? professor: if you need waterbecause it's some kind of a health thing, fine.
but i do not want to see a wholebunch of people drawing on water bottles. don't need it. you can go 50 minutes withoutyour little-- whatever. professor: you know why? i'll tell you why. it's not because i'm tryingto be a control freak. this is a chemistry class, butit's chemistry-centered.
you didn't just come to mit tolearn some geeky techno stuff. you're preparing for aprofessional career, and part of that is how you behave, howto act as a professional. and you cannot learn behaviorby doing problem sets. how do you learn behavior? you learn behaviorby observation. and how does oneteach behavior? by modeling. if you're in some high-levelcommittee meeting and all of a
sudden your cell phone goes offand you're scrambling and you can't find the damn thing,it's in the bottom of your briefcase, right? i can't tell you howvulgar that is. you're in a professionalsetting, you commit professional suicide. and i need to tell you that. if you think it'sok you're wrong. so let's get in the habit.
disable the damn thing. what do you need? you're going to callyour stockbroker? what's so important right now? and on an exam, that thing goesoff i take the exam in front of everybody and-- [making ripping noise] professor: --we introduce adefect, it's called a tear. professor: and then i put a zeroon it like this, with a
circle around it. it's called a donut. professor: all right. now let's talk aboutsome lighter things, more upbeat things. look, i want you to succeedin this class. now how are we goingto succeed? you go to the listingin the bulletin you'll see this, right?
and you zoom in hereit says 5-0-7. what's this mean? well the 5 is 5 contact hours. 3 here and 2 withyour recitation. the 0 is lab. there's no lab withthis class. so what's the 7? the 7 is the reading,the homework, preparation, et cetera.
i pledge to you, you give me 7hours-- you go to the 5 hours contact and 7 hours-- you will not just pass thisclass, you will flourish in this class. how do i know this? because i used to chair thecommittee on admissions and i've read applications. i know the quality of individualin this room. you should have seen, there were11,000 applications piled
up like this, each dossier likethis, and they just get copied down on a four-by-sixcard. we get here on a presidents' dayweekend and we got stacks and stacks of the cards. we're looking at your wholeacademic life is on a four-by-six card. and i pick that upand i go, yes. literally at this speed. about 45 seconds.
no. professor: hell no! professor: that's how i spentpresidents' day weekend. and so you got through a verygrueling selection process. what's the corollary of that? listen carefully to this:everybody in this room has the intellectual apparatusto pass 3.091. the only people who fail3.091 are people who choose to fail 3.091.
they choose not to come toclass, they chose not to go to recitation, they chose notto work the homework. i don't know why theymake those choices. but i guarantee you if you giveme this amount of time, you'll do well. it's straightforward. number one problem you are goingto face this fall is not secondary bonding, it'stime management. so i used to call thisstrategies for--
what did i used to call it? i forgot. i used to have it somethinglike, survival strategies. but i don't wantyou to survive, i want you to flourish. so i call it recipefor success. there are different venuesfor learning. ok? so lecture, that's here.
that's my responsibility. recitation, that's tuesdaysand thursdays. that's my staff. now reading, that's you. homework, that'd be you. weekly quizzes is you,monthly tests is you, final exam is you. professor: what we havehere is a partnership. see?
professor: so i'll do mypart, you do your part. you know, one of the thingsbeyond the basic learning of the chemistry that we're goingto attempt here is a transition. you are going to change inways you can't imagine. i want you to think about theway you are right now, and i'm going to ask you to thinkabout how you feel about yourself on the lastday of class. you will be amazed, and it'snot because you know a few
more chemical equations. and what one of the things thati want to see happen and to help facilitate is thetransition from student, which you are as a high schoolgraduate, to scholar. and the difference between astudent and a scholar is a scholar takes ownership ofhis or her learning. so you're going to takeownership of it. you know, is thisgoing to be on? are we responsible for this?
go back to high school. here you're a scholar. you say, how can i learnmore about this? that's the difference. so i think we'vecovered enough. i think we don't want to justhave the whole day, welcome to mit, welcome to mit. so what we're going to do iswe'll get into the lecture, and in the very brief amount oftime we have left i'm going
to talk about the beginningsof chemistry. we're going to talk abouttaxonomy, classification, nomenclature. and to help introduce this i'mgoing to refer to the writings of william shakespeare. we're going to integratesome humanities here. we're going to read fromromeo and juliet. maybe there are people herewho were admitted on the strength of the performancein romeo and juliet.
maybe one of you was romeo,one of you was juliet. maybe one of you didthe lighting. maybe one of you didthe set design. maybe one of you tookthe tickets. somehow you were involved,right? because we're all involved. so let's take a look. act 2, scene 2. romeo: "but soft, what lightthrough yonder window breaks?
it is the east"-- that's the east. east campusis that way, right? professor: "it is the east, andjuliet is the sun." that has nothing to do withnomenclature. maybe photon emission, but-- that's a joke. we'll get to it. now juliet: "o romeo, romeo! wherefore art thou romeo?
deny thy father andrefuse thy name. or, if thou wilt not, be butsworn my love, and i'll no longer be a capulet."see she's a capulet, he's a montague. you know, the hatfieldsand the mccoys. and this is a metaphor. it's as old as literature. it's about warring factions,two communities that can't stand each other basedon prejudice.
and then these two youngstersfall in love, and how love triumphs over hatred,and so on. it's powerful stuff andit's written here. romeo: "shall i hear more, orshall i speak at this?" remember, she's up high, he'sdoing "shall i hear more, shall i speak at this?" fellows,the answer to that question is don't speak. don't interrupt her. all right.
so now she goes, "'tis but thyname that is my enemy. thou art thyself, thoughnot a montague. what's montague? it is nor hand, nor foot, norarm, nor face, nor any other part belonging to a man. o, be some other name! what's in a name? that which we call a rose by anyother word would smell as sweet." that's properties,right?
"so romeo would, were he notromeo called, retain that dear perfection which he oweswithout that title. romeo, doff thy name, and forthat name which is no part of thee take all myself." beautiful writing. 400 years ago and it'sjust fantastic. well, that's no good. that's not the way itworks in science. in science we have to agree--
professor: we have toagree on the name. and so this is taken fromchapter 1 of the text, and this is the classificationof matter. this is about stuff and thedifferent forms of stuff. over here we have the simplestform of stuff, which is the element. and we're going to start herein 3.091 and we're going to work our way all the way throughthis table, starting with electronic structure andhow electronic structure
governs stuff. so let's start witha history lesson. we'll start with ahistory lesson. and the history lessongoes like this. what are the originsof chemistry? the ancient egyptian hieroglyphsrefer to khemeia, which was a chemical processfor embalming the dead. you know the egyptians were veryfixated on the afterlife. and the chemists, the chemistswere revered in that society--
not like here. they were revered in thatsociety because they knew how to prepare the bodyfor the afterlife. embalming is a chemicalprocess. a few years ago iwas in london. i toured the british museumand came upon this. this is 18 inches tall. it's the mummified cat. it's a fantastic exampleof mummification.
it's a beautiful-- most peoplego zooming right past it. they're looking at thebig dinosaurs and all that other nonsense. but this, this is beautiful. mummified cat. and then khemeia expanded toother chemical processes: dying of cloth, glassmaking,and metals extraction. the chemist could take dirtand turn it into metal. sorcery.
some things haven't changed. i'm in that tradition: producingmetal from dirt. and they were always looking foran overarching theme, to unite the heavens withthe simple elements. so the seven known,naked-to-the-eye, astronomical bodies were associatedwith the seven known chemical elements. and you could even talk inthis priestly language. so if you wanted to make abronze, which is an alloy of
tin and copper, you could say,well let's have the confluence of jupiter and venus. it's all there. mercury. why do we call it mercury? mercury's a metal that's liquidat room temperature. it's fast. because mercury isthe planet that moves quickest around the sun. very nice.
so this is what we knew2,400 years ago. we had the seven metals,carbon, and silicon. and the beginning of the shiftfrom practice to theory, or from craft to science, is withthe work of democritus. democritus, who livedaround 400 bce. democritus, who was greek. he described the physicalworld as consisting of a combination of voidplus being. void plus being.
these are lofty words. listen to this. void, being not somelittle equation. it's big, big ideas. and how did he describe void? void is something that wewould recognize, in his language, as akin to what werecognize to be vacuum. and being, he said, wascomprised of an infinity of atoms.
he coined the term "atom.""atom" comes from the greek tomoi, which is to slice. and then if you put "a" in frontof it as in apolitical or amoral, cannot be sliced:indivisible. the atom cannot be sliced,and so to these atoms he attributed these properties. they're indivisibleand eternal. i mean, this takes you all theway to e equals m c squared. from 400 bce, and that's allhe had to work with.
this is brilliant. absolutely brilliant. but to show you that thingsdon't always go in a linear fashion for the better,along comes aristotle. aristotle, another greek, and hedecided, nah, we don't need all this carbon, sulfur,and so on. he said, we will have fouressences that will describe the earthly world. four essences.
and here are thefour essences. earth, water, air, fire. so those are the aristotelianessences. and there's actually afifth essence that describes the heavens. that's why we say somethingis quintessential. it's heavenly, it's et cetera. so these are thefour essences. and then it gets even worsebecause he has compounds, a
combination, so you can takefire plus earth and make dry, earth plus water make cold, airplus water make wet, air plus fire make hot. this is nuts. professor: and it dominatedscience for a long, long time. because we know really earthis an aggregate. it's an aggregate of differentminerals which are compounds. water, as you know,is a compound h2o. fire is the productof combustion.
it doesn't even belongin this set. and air is a solution. it's a homogeneous mixture ofnitrogen, oxygen, argon, rising levels of carbon dioxide,sulfur dioxide. and if you're next toan aluminum smelter, tetrafluoromethane. and so on and so forth. and finally this thingwas knocked down. so we can look at this chartand go back to this one and
say, now we can makethe connections. here's the way the elementslooked at the time of the american revolution. the alchemists gave us arsenic,antimony, and bismuth in the 12th, 13th,14th centuries. in 13th century india, therewas zinc isolated. there's a tall zinc pillarstill standing there. platinum is an american metal. it was unknown tothe europeans.
it was discovered when thespanish came to the americas. actually, it's kind of ironicbecause plata is silver, so platina is sort of like adiminutive of silver, which in point of fact is backwardsbecause silver melts at 962 degrees celsius, platinummelts at 1768. it is nobler than silver. it has catalytic properties. it is even fashionable injewelry now if you know how to work with it, because gold meltsat 1063 and platinum
melts at 1762. a lot of jewelers can'twork with platinum. it's too high-melting. it's a fantastic metal. it's an american metal. professor: it really is. i mean it's an american metal. i didn't make this up. and then we see theseother elements.
discovered, discovered,discovered, discovered. now we see modern science. so what does it mean,discovered 1766? there was no hydrogenbefore 1766? they found it? it means that cavendish isolatedit and documented its properties. hence, it was discovered. now i've been cheating here.
this is actually lined up ina way that we already know, where the story is going toend with this, with the periodic table. i'm just lying them on the tablein a way that makes it possible to anticipate. but this was the first table ofelements that is of record, and this was by john dalton, theenglish chemist, who put these in order of atomic mass. they're organized in ascendingorder of atomic mass.
and he also started a systemof chemical symbols. and you can see that iron hasan "i" with a circle around it, and zinc has a "z" witha circle around it. and the swedish chemistberzelius said, you know i don't think the french are goingto like to use "i" with a circle around it for iron,or germans aren't going to like that. we better choose somethinga little bit neutral. so they chose latin.
and that's why iron is "fe" forferrum, and gold is "au" for arum, and so on. but this was thefirst attempt. john dalton actuallywas a polymath. he was also working on vision,human vision, and he suffered from an affliction that ispresent in about 10% of men, which is red-greencolor blindness. and he did the original work onred-green color blindness. in fact, in some circles itis known as daltonism.
it's the same man,john dalton. other classifications. dobereiner in jena talkedabout triads. and if you took the atomic massof chlorine, added it to the atomic massive of iodinedivided by two, you get something that's nottoo far off the atomic mass of bromine. newlands was a musician andhe talked about octaves. so if you start here, if thisis a diatonic scale, so this
is c, d, e, f, g, a, b, c. so potassium lies an octaveaway from sodium. he was ridiculed. they said, have you consideredperhaps putting the elements in alphabetical order? they were cruel. scientists can be verycruel to new ideas. and, in fact, in your book thisis some of newlands work, and you can see to what extentit helps understand things.
but the first properorganization came in 1869 with mendeleyev, and also 1870 withlothar meyer in tuebingen, the periodic table as we know it. and this is the set ofelements that were known at the time. and this is a page from thepaper in which mendeleyev published the periodic table. and here's the smokinggun right here. it's right here where he says,in this new system, in this
proposed system, there are verymany missing elements. very many missing elements-- that was the key. because he knew that even thougharsenic has the atomic mass next highest to that ofzinc not to put arsenic under aluminum, not to putit under silicon. it had more in commonwith phosphorus. so he put it under phosphorus,and so did meyer. but what mendeleyev did, whichwas a first, he said, there
are missing elements here. there is an element that liesbetween silicon and tin, and i predict what it'smass will be. i predict what it's chemicalformulation will be, how it will react with oxygen. the predictions. and how did he get this? because he used to travel bytrain and he would sit in the train station on his trunkplaying solitaire.
and he'd be going downone suit, and then there'd be a gap. and he'd go down the other suitand he could go farther. and so the concept of, i knowthere should be an eight of spades here, but i haveto stop at the nine. i've got a seven but there'ssomething in there-- triggered his imagination andled him to have the courage to say, there are elements thereand i will predict their and when they were discoveredhow close he was is shocking.
absolutely shocking. so we'll get to that next day. but before you go i wantto leave you with this. this is the portraitof mendeleyev that you typically see. this man on in years,disheveled, sort of mad scientist look. don't remember that. look at this.
this is mendeleyev, age 35, whenhe proposed the periodic table of the elements. we'll adjourn. we'll see you on friday.