Chem(9:9) ch2 intro.docx

### Chem(9:9) ch2 intro Speaker 1 00:00\ Very serious. Is that did you go those? You have to end up just now? Were you unable to attend? Or did they just say, are you unable to attend? Okay, for those of you who are unable to attend, I have information for people you should reach out to deal with t...

### Chem(9:9) ch2 intro Speaker 1 00:00\ Very serious. Is that did you go those? You have to end up just now? Were you unable to attend? Or did they just say, are you unable to attend? Okay, for those of you who are unable to attend, I have information for people you should reach out to deal with the images. Okay, and then ii think I do with this day work not now the third days of probably, although they worked very quickly and all this stuff. I think that. Speaker 2 00:33\ pretty soon this is all going to be resolved. And let me get my tablet out, and we get to show you the road. Speaker 1 00:42\ Does anybody have any questions on getting set up here? Speaker 2 00:46\ We use this time of discipline earlier today. When I took in class, I had a little bit of trouble with my professor. I\'m gonna see how that works out. Speaker 1 00:57\ And I. Speaker 2 00:59\ am for a particular reason right now, I am on zoom added for request. I can relocate that what i\'m doing today for our class. It won\'t be all classes just today. Just want to let in case you have my answer. Questions, I think about reporting, not reporting, but so having somebody write down, captures for this, ii just want to go. I should make you aware of that. In case, you want to ask her to answer your question. After we\'re done, if you have questions after class, i\'ll shut this off. I think we should be good at all. Good luck. That\'s great. Ha ha ha. Speaker 1 02:03\ Not like today. Speaker 2 02:04\ about 6 months that really? Speaker 1 02:12\ Yes. And it will be better. Speaker 2 02:14\ So this is good. You can\'t see that yet, but to 1 second, we\'re gonna pick up on, we left off at accuracy, precision in the last class. I think when I started the last class, I probably I probably over that a little bit more than I should have been previous class, but that\'s a case in. I need one. Now I need to get the other document. That\'s what we\'re going through today. And this is where we, I don\'t know. I think this is not what we did. This is where we left in the last class. And that\'s where we\'ll kind of start today. So the difference between accuracy and precision, you\'re kind of talking about this stuff in your lab. This week. I think I saw somebody from a free lab to have a question related to this. And we covered that part. Speaker 1 03:26\ Now we\'re gonna go to mathematical treatment. Speaker 2 03:30\ of measurement results. And this is pretty much going to be. Speaker 1 03:38\ dimensional analysis. Just a brief introduction to it and where we get these conversion factors. This is section 1. 6 dimensional analysis. Speaker 2 03:53\ We also call it the factor label method. Speaker 1 03:56\ Really, it\'s just a method for the unit convergence. And whatever we convert from one unit to another unit, what we are doing is we\'re not changing the. Speaker 2 04:10\ amount which is changing the units, and we\'re using a conversion factor to do that. Speaker 1 04:17\ The question you might have is, where do we get these conversion factors? And how do we use them? I\'m going to show you where we get them. And in on exams and on quizzes and so on, I will give you either inequality. I\'ll give you the flat out conversion factor, but I want you to understand the difference between the two that I want you to understand where we get conversion factors. Speaker 2 04:44\ that you understand why we can use either one conversion factor or another one for a particular and breaking. These are qualities. These are from the open stacks, sex. There are plenty of others. This is just a handful, for example. Speaker 1 05:01\ we have. Speaker 2 05:03\ inequalities for measurements of length. Speaker 1 05:07\ volume, and mass. So we\'ll just take across the top row there that we have 1 meters, 1. 5936 yards. That\'s the equality. Speaker 2 05:17\ 1 meter is equal to 1. 0936 yards. A 1 liter is equal to 1. 0567 ports, and a kilogram is equal to 2. 20. Speaker 1 05:29\ for ￡6, these equalities enable us to convert between meters and yards or meters in quartz or kilograms and pounds. And wherever else the equality happens to be, the quality is the where we get our conversion factors. We learn about how we get there and why we can use them. We\'re going to take that first equality that said 1 meter is equal 1. 0936 yours. Right now, what we\'re doing is we\'re understanding where we get conversion factors and why you can use them. If we take this equation in both, divide both sides by 1 meter, which is where I should have moved here, we have 1 meter over 1 meter equals 1. 0936 shots divided by 1 meter. And I can just go here with my happy pen. This is of the work and draw. Speaker 2 06:36\ And i\'m just gonna put a strike through this. Speaker 1 06:40\ here, because that becomes one. What do we know about? The number one specialist? Because we can multiply anything by one. Speaker 2 06:51\ and not change its value. Speaker 1 06:54\ Our conversion factor here, and we multiply by it, provided that units are consistent, and you shouldn\'t be taking pictures of the stuff there. Speaker 2 07:05\ They can notice that how you learn and learn about different pictures. Speaker 1 07:09\ And if we can multiply anything by this, it\'s like multiplying by one. It\'s not going to change the length. Or in this case, the length is not going to change the length. It\'s just going to change the mean, provided that the units are consistent. Speaker 2 07:27\ We multiply by this conversion factor of the slave multiplying by one. Speaker 1 07:32\ This conversion factor allows us to convert. Speaker 2 07:35\ from meters to the arts whenever music conversion factors. Speaker 1 07:41\ you\'re converting one quantity, not a fractional quantity, but a quantity to another. Speaker 2 07:47\ You use the conversion factor that has the quantity that you want to convert to in the numerator. We wanted to convert from meters to yards. We can use this conversion factor. What if we want to convert to the reverse? What conversion factor will be used? Speaker 1 08:05\ Short cutting it. We can just say put this one. Speaker 2 08:09\ Now we can go from the arsenios. We got the drop off and 1. 93 starting well. Speaker 1 08:14\ But let\'s see how that\'s valid. We\'re going to consider our equality again, but this time, instead divided by 1 meter, we\'re going to divide both sides, but 1. 0936 yards. And you see what happens. Now, this side of the equation. Speaker 2 08:35\ becomes one that cancels. Speaker 1 08:37\ And now we have a conversion factor here. Speaker 2 08:41\ that allows us to convert from yards to meters. Speaker 1 08:44\ Those two conversion factors. This one. this one, when we multiply them, providing units are consistent. It\'s just like we\'re multiplying by one. Speaker 2 08:58\ We\'re just changing the units. That\'s why we can use it, and that\'s why we can use it, sometimes with the arts on top and sometimes with the leaders on top. This conversion factor allows you to convert from use to yours, and the next one from yours news. Let\'s put this. Speaker 1 09:16\ copy in action. If we are to convert between convert from 2 meters to yards. Speaker 2 09:23\ we reduce the conversion factor that has yards in the numerator. Speaker 1 09:30\ What happens? Leaders cancel. We get 2. 187 to yours since we only have two sig figs here, and we don\'t include significant digits in conversion factors of the data that they don\'t come into our consideration. Speaker 2 09:49\ We report the answer 2. 2 years. Speaker 1 09:52\ See that now doesn\'t that empower you? I on an exam, I can give you the conversion factor straight away where I can give you the equality. You may have to go through the steps. I just did you just have to make that fraction that you would get? Speaker 2 10:10\ Either you are over meters or years over yours. Speaker 1 10:15\ Every quality that you ever see can give you two conversion passages. Keep that in mind like for other classes and so on. When you say I can\'t answer this, you can. Speaker 2 10:27\ you just have to know what your resources are. Okay. Let\'s see what\'s next. Let\'s convert it back just for a case. Let\'s convert our 2. 2 yards back to 2 meters. If we\'re going to convert from yards to meters, now we use this conversion factor that has meters in the numerator. Speaker 1 10:46\ And then we can do this. And when we do chemistry, questions, many chemistry questions. Speaker 2 10:55\ no pen attendant. Speaker 1 10:56\ boiled down to multiple community conversions. Speaker 2 11:01\ That\'s it. We\'ll see this play out and bring your attention when it happens. Let\'s try this one. Speaker 1 11:11\ Invert 9. 345. Speaker 2 11:14\ ports to meters. Speaker 1 11:15\ And here\'s the quality. I know you want to do. You can just quick write down the two conversion factors, or you can go ahead and divide both sides. Speaker 2 11:27\ luggage and get your investment. Please sum your name, and then. So how\'s the same things for? Speaker 1 11:36\ So the same things, let\'s go back. Whenever you do questions like this, you only consider the measured value. You don\'t consider. Speaker 2 11:50\ the conversion factor, only the measure the value of your convergence. Thank you. You\'re welcome. Speaker 1 11:59\ I didn\'t catch your name again. Can you tell me again? Speaker 2 12:02\ I\'ll see you a. Speaker 1 12:03\ little bit loudly. I\'ll sign. Sunny. Thank you all. Speaker 2 12:09\ I\'ll see it back on the back here now that I showed you the answer. My sport is some of. Speaker 1 12:15\ we\'re gonna take 9. 3454. And here this is our measured value. Speaker 2 12:22\ We have four state phase with it. And this is our conversion factor. Speaker 1 12:28\ When you put meters on top, words cancel, and we get 818448. Pretty straightforward kind of thing. Speaker 2 12:38\ It is, but remember, we start letters on information, so you go out the practices so that it becomes set nature. Let\'s start when it takes a few steps. Speaker 1 12:47\ What is the volume invaders. Speaker 2 12:51\ of one ounce? Speaker 1 12:56\ Now, do you expect that number wherever we get to be very, largely, very small, just like using everything all of you? Speaker 2 13:05\ Yeah, since it\'s gonna be small, so we\'re starting to announce is much smaller than a leader. Speaker 1 13:09\ Very good. That\'s always you want to do that analysis. Once you get an answer, you want to say, are my units reasonable or correct? Is the number of magnitude I have? Is it reasonable for the conversion that i\'ve done? If it\'s not, then you just put the brakes on it. Speaker 2 13:26\ Start all of us yourself up, start over. So here are two conversion factors. Speaker 1 13:32\ I don\'t know how much of this I put in the notes. I hope that it\'s not there, or if you\'re not looking at it, but i\'m gonna give you. Speaker 2 13:40\ 30 seconds to work together or with yourself and see what you come up with. Now, whatever the. Speaker 1 13:46\ red hand goes on 12, i\'ll say, stop. So go ahead. You can talk to each other about this. Speaker 2 13:58\ 15 seconds. So pressure and you have your calculators operate in the evening. I will give you 57, which is. Speaker 1 14:19\ right. Now, i\'ll bet you that there are a lot of people there didn\'t write this down. I\'ll bet you why you just did the thumb things in your head. And you probably have the right answer. Speaker 2 14:29\ too. That\'s dangerous to be really good to do that. Speaker 1 14:33\ Because when you get into other questions, you have to watch 653 steps and everything that can really trick you up, even if you know what you\'re doing. So make yourself go through with these steps as you\'re learning. When you get better at it. Speaker 2 14:47\ You have a question. Speaker 1 14:50\ But let\'s see what we have here. So we when we do these unit conversions, we always start with the number that were given, like, what do we have to convert from? That\'s always. All right. Then we use the conversion factors that allow us to converge where we\'re going. Sometimes we have to do that sequentially. We have the qualities that make the mayor to the court and then court out. Speaker 2 15:16\ We started with bounce. That means we have to use the conversion factor that has answers in it. So we can convert from answers. Then we can use our second conversion factor for the top conversion, the yellow conversion factor to convert from quartz to leaders. We have 1. 000 answer. So that\'s forcing things. And we prefer our number to four significant digits as we have four here. We don\'t worry about these in terms of significant digits. They\'re just converting factors. Speaker 1 15:50\ And then alice is cancelled, works. Speaker 2 15:55\ cancel. And we have our answer in the years. Whenever we write in scientific notation to show the correct number, significant digit, we have 2. 957 times 10 to the negative second. Leaders. I put it perfectly well left like that. Speaker 1 16:13\ Okay, either way would be correct. Speaker 2 16:15\ That makes sense. Those are kind of fun that are really puzzles. You have a lot of practice. I suggested some questions at the end of the chapter, and then also the achieved questions are good. Speaker 1 16:30\ This link, if it\'s not active in your document, it\'s active in the page, the view of it. Speaker 2 16:36\ This is a nice place to do to go. There is a nice video on dimensional analysis there. Speaker 1 16:41\ It\'s not a method that I like favor. Speaker 2 16:45\ but some students do something, some students learned by the method that this guy shows. So i\'ve got to put up there for those of you who find useful. Now. Speaker 1 16:56\ temperature units we\'re going to have to convert. We have to convert among temperature units. We have three temperature units that will use throughout this course, fahrenheits, celsius and kelvin. Kelvins are restricted, usually to. Speaker 2 17:13\ learn about chemistry, thermodynamics, and electrochemistry. Speaker 1 17:19\ And. Speaker 2 17:23\ we\'ll have a look at the convergence here, because a lot of times, especially with the thermochemistry and thermodynamics, you will be given a celsius temperature. And you have to converge the problems. Let\'s have a look, this is just a different skills. I i\'m not going to spend the time getting into the means about these pictures. Speaker 1 17:46\ though, show you. Speaker 2 17:47\ how we get these the conversion equations for these. When you convert from high temperature to another, it is really just a conversion. It\'s a unit conversion. Speaker 1 17:58\ but it looks a little bit different. Speaker 2 18:03\ The reason that looks a little bit different is we have to come from a different radiation among the degrees prepared by celsius. Speaker 1 18:13\ And in most. Speaker 2 18:15\ how many of these? In most facts, I want to fix something here. Phase variable will be developed into insert the equation. I\'m just gonna do the munich conversion here. Maybe you have equation here on this issue. So then put 1 kelvin for do celsius. Speaker 1 18:54\ And that will make this week. Speaker 2 18:58\ And i\'ll tell you why did that in a second photos. And I want to tell you, all right. Now let\'s look at our conversion for converting from temperature and degree celsius to the temperature. Speaker 1 19:16\ probably convert from fahrenheit to the ℃. Speaker 2 19:27\ If you have a temperature in fahrenheit, you want to convert to celsius, you do the temperature and degrees fahrenheit - 32 ℃. So you get some number that has three fahrenheit as the unit. Speaker 1 19:42\ You multiply by 5 ℃ times 90 ℃ and fahrenheit cancer. Speaker 2 19:49\ You get your answers in the celsius. Speaker 1 19:52\ I think many of you have just like, wrote memory, what we need to calculate to do this calculation. You don\'t have to write a lot like this all the time, but i\'d like to show to you just to remind you that this is just a unit conversion. There\'s nothing mysterious about this. And then if we want to convert. Speaker 2 20:12\ from ℃ to increase. Speaker 1 20:16\ fahrenheit, we multiply the temperature and ℃ by 9 ℃. Speaker 2 20:23\ Over 5 ℃. You can see these celsius cancel. And. Speaker 1 20:27\ then we add, where are we getting fahrenheit? Use fahrenheit to 32 to get our temperature in fahrenheit? Speaker 2 20:34\ It\'s just a unit conversion. Speaker 1 20:37\ The one that is probably the easiest one to do is the conversion between celsius and kelvin. And we just add to them. Speaker 2 20:47\ who\'s calling that? Isn\'t that it\'s just so you do so many times. You even think about the units. You just know it\'s right. Speaker 1 20:54\ What we can think about is there\'s 1 °. Speaker 2 21:01\ 1 kelvin for ℃. That\'s our conversion factor. The temperature and kelvin is our temperature degrees celsius times 1 kelvin for ℃ + 273. Speaker 1 21:15\ That\'s why you can just add. Speaker 2 21:18\ the resources to. And here ii was 7. 5. Those are temperature conversions. You have plenty of practice, at least some achievement or some that I suggested to do in the chapter. Speaker 1 21:32\ And. Speaker 2 21:37\ i\'m going to make this example for you guys. This is you can practice on them. Speaker 1 21:49\ If he comes off the stars tonight at 8:00 pm and zoom. Speaker 2 21:53\ we might be able to go with somebody. The link will be in chemistry. This we can zoom section, I will take it to zoom or click on the pink to zoom on your landing page. And then I will take the zoom section campus. At 8:00 pm i\'m having an offshore tonight. All right. And with that, we can say goodbye for chapter one and hello, chapter two. This is where we start to get into some countries. Here. Chapter two is on atoms. Speaker 1 22:35\ molecules, and ions. And if chapter two begins with dolphins, atomic theory. Speaker 2 22:43\ and the adults are coming through and no certain campuses, you want to come out. We\'re going to talk about the postulates of the country. You have five of them. Speaker 1 22:54\ Whatever i\'m going to keep in mind with is that dolphins atomic theory, we know now that it\'s not 100 % correct. Speaker 2 23:02\ There are some subtleties we have modeled or modified a little bit, but in general, it all fits with what we know about. Speaker 1 23:12\ atoms and molecules and chemical reactions. Speaker 2 23:17\ And some laws. Let\'s have a look at it. The first postulate is that matters composed of tiny, indestructible particles called atoms. Speaker 1 23:28\ We now know society, but they\'re not indestructible. Speaker 2 23:33\ So we can do some damage to the book, but not by chemical means. Speaker 1 23:37\ And atoms in chemical reactions retain their identity. Atoms. In a chemical reaction, atoms at first are running together. They\'re sharing electrons with other atoms. When a reaction occurs. Speaker 2 23:53\ some bonds are broken. Speaker 1 23:55\ and new bonds are made, but the atoms don\'t change identity, the compounds, too, because the average standard range, an analogy that I used in my 2:00 pm class was like you can think of atoms as legos. You have different shaped legos, you have different colored legos, whatever. And let\'s say. Speaker 2 24:19\ on this side is the equation. You build a house with your lagos, and you build a bicycle from your lagos. Speaker 1 24:26\ Then there\'s a chemical reaction, and then those legos got a certain number of them, and they\'re connected a certain way. And then there\'s a chemical reaction. You tear apart your labels, and now you rebuild, and you build a boat and fishing rod. You use all the same legos. You just connected them differently. There\'s something else. Now. That\'s nature\'s lego is the atom. It\'s just the way that they are connected that changes in a chemical reaction. We have the same number of the same type. And the products, as you really react in, the reactors they\'re connected with me. Speaker 2 25:07\ That\'s the first first postulate. The gulf countries. Second one is an element is composed of 1 type of atom. Speaker 1 25:20\ Here, I grew up here in this little example. Imagine that this is a sample of sodium, sodium metal, not sodium ion. And remember, sodium is an element. It\'s a metallic element. The atoms in the metal are aligned in a nice, neat lattice. And at the center of an atom is its nucleus. And in the nucleus, there are protons positively charged particles, and there are neutrons that are neutral particles and contribute to the mass of the atom. It\'s the protons, the positive charges that you see here, that in part of the identity to the atoms of an element, for example, hydrogen has one proton in its nucleus. Any atom has one proton, if that\'s hydrogen, giving has two protons in this nucleus. He added has two from the class last evening. Lithium has three, the atom that has three protons into this. It\'s lithium atom. And we\'re going to talk about effective nuclear charge and electro negativity today in this context. The effective nuclear charge and electro negativity all relate back to the number of protons in the risk or the atomic number, which is a way of saying the number of photons in the vehicles. But for our battle, all of the mvi lined up nicely. And around all of them are electrons. We say that those those nuclear are in a sea of electrons, the electrons are being localized about the metal. And that\'s why those are conducted. an element such as sodium as these atoms. And. Speaker 2 27:22\ each sodium atom has the same number of protons in the increase level. Let\'s look at. Speaker 1 27:29\ the next oscillator. All atoms of an element have the same properties, same mass, and as of what element different properties. Speaker 2 27:39\ from atoms of all other elements. Now, we know that this is also not true. Speaker 1 27:46\ because we\'re going to see it might not be today, but it will definitely be the next class. We\'re going to find out that we can have an atom of sodium that has. Speaker 2 27:57\ same number of protons as another atom, sodium, but the number of neutrons might be different. Speaker 1 28:06\ The neutrons can vary. It\'s still sodium, because the number of protons of the nucleus give that at the end, the number of neutrons contribute to the mass. What we have to ask of the same substance that have the same element that have the same number of photons into these different numbers of neutrons. Speaker 2 28:31\ we call them isotopes, and they\'re called isotopes, and we\'ll get into that specifically. Speaker 1 28:37\ But it\'s just another case of where all the series fit the knowledge of the time, but had to be adapted a little bit with that new information. Next is. Speaker 2 28:53\ 4th postulate. States. Speaker 1 28:58\ a that a compound is composed of atoms that are chemically combined, and simple whole number ratio, just like the legos. You put them together and you make the same structure of the same number of atoms. Both of those structures have the same ratio of lego, different types of legos. And then they give a compound. Speaker 2 29:23\ The numbers of atoms of each of its elements are all in standard shows. So I said about the lagos. Speaker 1 29:31\ So. Speaker 2 29:32\ let\'s go to the first one and chemical reactions as rearranged to get substances that differ from those present before the reaction. Just like your original lego house, and I forget what the other bicycle, the house and the bicycle, you rearranged everything and how you made a boat and fishing car. You just rearrange the other. Speaker 1 29:58\ that leads to our law of conservation matter explains the law of conservation of matter. Speaker 2 30:08\ So. Speaker 1 30:08\ people. Speaker 2 30:10\ new law of conservation of matter and dogs upon theory said this might be what of course. Speaker 1 30:18\ we have to modify it a little bit, but you can see law conservation matter how it falls from these postulates is in a temporal reaction. Matters either created or destroyed. We\'re just reading the nature\'s lagos. What do you guys together differently? Then the law of conservation matter here, I believe that\'s a nice video of birth. Speaker 2 30:45\ mercury, oxide, pure oxide, and go into mercury, metal, and oxygen. Speaker 1 30:52\ It\'s a nice demo. Your link on your page might not be active. However. in the video page on canvas, you should be able to. And also there\'s a nice bio of anton rossi. I think it\'s important for you guys to just say, i\'m not gonna ask any questions about him, but I think it\'s important to think about how it was back in the day when people didn\'t know any of this stuff. And the light bulb comes on for a few of them, and they have to go out and convince everybody that this is true with very little evidence for all these reasons. And meantime, everybody they\'re trying to convince. Speaker 2 31:33\ they\'re most concerned about pink and roof over their head and pink on the table. Speaker 1 31:37\ You\'re gonna tell them, right? You have to listen to this of wealth conservation matter. Notice those people had a lot of uphill battles to get. People can accept this information and to value it. Speaker 2 31:52\ Iii think that when we have to learn this and you see some of the things that we\'re going to learn in this class. Speaker 1 31:59\ yes, it\'s difficult as to take, but imagine being the person that had to first recognize it, then explain it. Speaker 2 32:07\ and get it accepted. It was pretty impressed that these people really, really impressive people. And sometimes in general society, they get kind of forgotten about. We just use what we learn from them. Speaker 1 32:20\ You never realize the sacrifices they made, you get that information in your hand. Speaker 2 32:25\ So there is that, okay. Speaker 1 32:27\ and then another one of these people joseph browse came up with the law of definite proportions or the law of constant composition. So all samples of a pure compound contain the same elements in the same proportion. If you guys have a sample carbon, monoxide or army isotropic, good, for example, and you guys do and you guys do, you\'re going to get the same proportion of carbon, hydrogen. If you were to do analysis. Now, on notes that I provide for you, I intentionally left this part blank, as I would like for you to see what\'s happening. What we\'re doing is we\'re taking our sample, our mass of our carbon and divided by the mass of our hydrogen to get the mass ratio of carbon to hydrogen in each of these samples. And since each of the samples is of, I saw, I think, then that\'s good. Speaker 2 33:23\ because we get this ratio of 5. 33 a month, each sample. And that\'s that\'s what the law does. For a lot of constant competition says, if it\'s the same substance, it\'s always going to have. Speaker 1 33:37\ the same. Speaker 2 33:39\ mass ratio. And we\'re going to find also chemical formulas that will be deceived for that. Speaker 1 33:44\ And then we have. Speaker 2 33:47\ that was a lot of definite proportions for a constant opposition. And then from golf. And we have a lot of multiple proportions. Speaker 1 33:55\ Because we know that carbon and oxygen can form two compounds, Speaker 2 34:01\ carbon or war, but carbon monoxide, carbon dioxide, ok. Speaker 1 34:08\ how do we explain that? Speaker 2 34:11\ Those are the proportions says when two elements and the carbon and oxygen for two different compounds. Speaker 1 34:21\ masses of p that combined with 1 gram of a can be expressed as a ratio of small numbers. And those small numbers. Speaker 2 34:30\ are the subscripts in the molecular formulas that you will write for compounds. I have a little thing here that shows that. So for carbon monoxide, you have 1. 3321 grams of oxygen per 1 gram of carbon. Speaker 1 34:50\ And for carbon dioxide, you have twice as much. Speaker 2 34:55\ of oxygen or wonder after analysis. That\'s how we\'re getting these chemical formulas. Speaker 1 35:02\ Co. Speaker 2 35:06\ for carbon dioxide and co two for carbon dioxide. Speaker 1 35:11\ Now, what do you need to know for these? You need to recognize the laws. Speaker 2 35:16\ Now, I if I have nation or something, you match on who is matched a lot in the person or the law to describe. And i\'ve already said this. So we\'ll move on to the next. Speaker 1 35:35\ This is the evolution of upon theory we\'re talking about now. And this is nice because of what it is showing. Speaker 2 35:42\ is what we talked about in the first class is when we talked about the scientific method, this is the scientific method. Speaker 1 35:49\ play out over decades century. Speaker 2 35:52\ right? Speaker 1 35:53\ And it will continue to play out. This is why sometimes like if there\'s something in the media, I didn\'t get the father and people they want an answer. They think the general public they just wanted the answer and scientists are like for the scientists, it\'s perfectly valid to say it could be this. It could be this. We\'re pretty certain it\'s this right now, but that might change. And for a scientist, it does the state of things, and it\'s the best we know that we have to work with that. But isn\'t it true that most people, your life they want an answer? And is either is this, what\'s that? And little tolerance for it could be this or that. And under these circumstances, it\'s this and undergoes is that it makes it difficult to convey scientific Information. And when series evolve, remember, it doesn\'t mean they\'re invalid. It just means they\'re adapting to new Information. Just like some scientists explanation for maybe some event on the earth, we have this exclamation by a few years of what we didn\'t know. We had that explanation since they modified. Speaker 2 37:10\ to the best of the knowledge. That\'s what you\'re given. And so almost upon the theory, that was the best of his knowledge at the time. Now we learned more, and there\'s some of it. Speaker 1 37:21\ By the end of 1,800 scientists degree that matters composed of ours. So that\'s a good thing that they got it down to that. Speaker 2 37:29\ But then ours themselves are made up of small particles and all the to his knowledge that was as small as you get. But now even more, there are smaller particles, proton, the neutron. Speaker 1 37:45\ an electron. And how in the world did we know that those were there who figured that out. Speaker 2 37:53\ that person was not like a rabbit. This is thinking about what about the atom, all the people who are doing this. They were thinking about little bit more depth about life. By the end. These experiments so that he had ads have smaller particles. Speaker 1 38:12\ ads have a nucleus that has neutrons and protons, like I introduced earlier. Speaker 2 38:18\ New frauds and mutual, like I mentioned. Speaker 1 38:20\ And. Speaker 2 38:22\ we can also call that uncharged. That\'s what you charge neutral. So I by that. And photons are positively charged particles. Speaker 1 38:32\ that the identity of each atom depends upon a number of photons in the absolutely. That\'s very important. Remember, the number of photons for a sample of an element. Speaker 2 38:42\ Each. Speaker 1 38:43\ each atom has the same number of protons, but it could have different numbers of these. Speaker 2 38:49\ That\'s my male in the school. I think that\'s the right sort of like that for useless. Speaker 3 39:01\ Yeah. Speaker 2 39:01\ Everybody always grew up and I maybe I should often do that. There stop, sorry about that. Now how my EMAIL is. So sure you should, sorry for that. Speaker 1 39:22\ that a number of protons in the nucleus is referred to as an atomic number, the number above the symbol of the element in the periodic table. That\'s the number from but on the nucleus. And this is how I\'m going to start to reveal to you how that periodic table contains all the Information you need to answer any qualitative question. Speaker 2 39:44\ that anyone. Speaker 1 39:46\ ask you and we\'re building, it\'s not gonna happen overnight, but you stay with me. And that\'s going to be a powerhouse resource for you at the end of the semester. So that is the atomic number protons in the nucleus. And we\'re gonna see this in a second. Protons and neutrons have about the same mess, not exactly. They\'re about the same mass. And electrons are various distances from the nucleus. Speaker 2 40:11\ Let\'s have a look at these relative masses and the particles. Speaker 1 40:18\ Now, remember this. These people didn\'t look these numbers up in the table. They had to experimentally determine them. Imagine how it was when they realized that proton and the electron have the same magnitude, charge, absolutely to us is like, I hope I can remember that. But to them, that was a big summary. The magnitude of the charge is the same 1. six seven five ten to the - 19. Cool? It\'s just that. Speaker 2 40:51\ the electron is negative in charge and the protons, the opposite charges. Speaker 1 40:57\ and neutron has no charge. Imagine. Speaker 2 41:03\ Dalton said Adam is the smallest thing, and then these guys come up and say, wait for the brakes. There\'s something smaller than the atom. There are particles in this atom. Imagine convincing people that they\'ve been trained to think that the atom is the smallest. So. Speaker 1 41:20\ all things that scientists have and then look at the masses. This is quite interesting in atomic mass units. The electron by far is the lightest particle here,. 00055 atomic mass units. The proton and the neutron are pretty close, but the neutron is a a little bit heavier. And if we take it a mass in grams. Speaker 2 41:46\ imagine this. Speaker 1 41:49\ how back in the day, you say the electron is 9. 1 × 10 to the 48 grams. Speaker 2 41:57\ How? Speaker 1 41:58\ I\'m going to figure that out? Speaker 2 42:00\ How can you? Speaker 1 42:02\ We can\'t even conceive of that small of a mess. but that\'s what it is. And the mass of the proton. Speaker 2 42:13\ in grams is past tens of - 24, and also the neutron + 10 to - 4. So you can see how much heavier the proton and and neutrons are. Here just by carrying those excellence. Pretty interesting, little facts about these. And those sizes and charges. Speaker 1 42:35\ have a lot to do with behavior. Now I want to show you this periodic table is what I said is I want to show you how these. Speaker 2 42:42\ the periodic table holds a lot of Information. It\'s useful. Speaker 1 42:45\ too. So if you look at the the numbers, let\'s look at, that\'s the number one, number three, number four, that\'s the atomic number. And those numbers tell you the number of protons in atom of that element. You have a walk sample with all the element. You have an add above it. You have one part of it in that one particle. If it\'s lithium. Speaker 2 43:13\ each nucleus has three photons. Speaker 1 43:15\ Now, the periodic table also tells us a. Speaker 2 43:19\ lot of other Information. Speaker 1 43:22\ I\'m gonna begin to tell you what it is, and then we\'ll pick up with it. Speaker 2 43:29\ When you come back from next class, I\'m going to put up the lights to show you this, okay? On the right on the board, on trade relations coming up to the left eye, 123. Speaker 1 43:44\ Look at that periodic table. And if this is our nucleus. i\'ll start at 48 by one hundred and four forty eight. Speaker 2 43:55\ by 100 % focus on going down. I\'ll give you a few minutes. I can see what. Speaker 1 44:02\ this is the nucleus that says that lithium is in period two, isn\'t it? So there will be three protons in it. I\'m not going to put three clauses. We have n is equal to one, then n is equal to two. Lithium has three protons, and then they have three electrons. The outermost one is theory. Then if we go to sodium has 11 protons and its outermost electron is out here farther from the nucleus. What we\'re going to consider when we come back is trends in effective nuclear charge and trends in electron activity based upon the influence that the new case exerts on its electrons. Right? Speaker 3 44:57\ And the next question, however, gradient and overseeing the movement, if there is a talking and thinking that you are doing any of these things that are involved in the United States that are involved in the world, broke. When bus is there? No, I got you. That\'s what it is. I was like Christian. Of course, it is mainly for nature. Going back home. Take a girlfriend. I\'ll take it.