Valence electrons. Now, valence electrons are actually pretty easy to understand if you know how to do a Bohr model. So, as a review, Bohr model, okay, we have energy. We have shells that hold electrons, okay?
The first shell holds two electrons. The second and third hold eight. After the fourth, it gets tricky.
There are a lot of exceptions. It can hold more than A. It's inconsistent. So really we're just talking about all elements until like calcium around that period, as we'll learn what a period is later. All right, so let's do a Bohr model of lithium really fast.
So we write lithium, okay? Lithium neutrally has three electrons, okay? Neutrally. So you're going to do the first energy.
level, or I should say shell, and you put in the first two electrons. That first energy shell, or the energy level shell, I should say. Shell is the right term.
Can only hold two, so we got to draw another one. Okay. This one holds eight, but lithium only has three, so we do that last one, and we're done. Okay, now what valence electrons are?
Valence electrons are the electrons on the outer shell. Okay, electrons on the outer shell. So in this case, the purple here, this purple electron right there on the outer shell would be the number it has, which is in this case, lithium has one. So one valence electron.
ok so if we look at something like nitrogen let's do the more model for nitrogen so nitrogen neutrally has how many looking seven electrons right so you're gonna i'm going to need to energy shells Alright, and then I fill in my first two. There's one, two. I got five more.
Can't put any more than two on the first outer shell, so one, two, and then five more. Three, four, five, six, seven. That's seven in total.
Now, the ones in purple are going to be the valence electrons. So how many valence electrons does it have? Five valence electrons. Okay.
Any questions about what valence electrons are? Great. Now I'm going to add a layer of confusion.
I didn't come up with this, but don't be too confused. There's a difference between valence electrons versus the valence. Okay. So the valence of an atom and a valence of a atom.
Okay, is the number of missing electrons to complete add or shell? It's confusing because the valence electrons is not the same number as valence. So if we go to lithium, let me get y'all copied that and then I'll explain.
The valence is the number of missing electrons to complete outer shell. The valence is just the number missing. So, for lithium, lithium is missing 1, 2, 3, 4, 5, 6, Seven.
It's got one. So the valence of lithium would be seven. What would be the valence of nitrogen then?
Three. Because we got one, two, three, four, five, but we're missing one here, one here, and one there to complete a set of eight. So we got three valence.
The valence is three. So be careful. Don't get confused between valence electrons versus the valence. It's something that I actually got wrong up all the way up to college.
They didn't really explain to me the difference. I thought it was the same thing. It's not. So, any questions about valence electrons versus valence?
Yes. Can you spin what valence electrons are? Valence electrons are just the electrons in the very outer shell.
So you look at the outer shell, and you see how many dots are on that, or you see how many electrons are on the outer shell. There's only one there. There's one, two, three, four, five there.
So that has a five. Those are valence electrons. No, the valence is the number missing to complete the outer shell. Okay? So valence versus valence electrons are going to be different.
Okay? Any other questions? That brings us to the periodic table, the structure of the periodic table.
Because you can use the periodic table to determine the valence without drawing Bohr models. So I need everyone to close their Chromebooks. Most of you all are paying attention, but there's a select few. We don't need them right now.
The structure of the periodic table. Lucas, close your Chromebook. The structure of the periodic table.
The first thing, and very basic, is that you need to know the term for columns and rows. Okay? Periods are the rows. Are the rows. And there's seven of them.
You can write seven of them if that is more clear for you. the groups are the columns. Something you're going to have to just memorize.
There are 18 groups. So, periods are rows, groups are columns. I don't have a very good way to remember this.
I guess if you all come up with a way, let me know. But I guess a G is more like a C, and a P is more like an R. I don't know. Like you see, there's the C in there, and then the R. You know, there's, I don't know.
I don't really, I just memorized it. Yes? Well, you don't have to, it's easy, you don't have to memorize that because you will always have access to a bare periodic table, and you can just count them. Yes? Like, how long?
On the, like, paper, it's like nine. Or like, it's like more than seven. Okay.
Okay, we'll talk about that in a second. In fact, I'll show you right now. Okay, so take the periodic table that I've given you. Okay, so it should be blank like this.
Go ahead and label them. You don't need a fancy color. You can use your pen or pencil. I'm going to just use the...
So this is one. That's not thick enough. One, two, three, four, five, six, seven, eight, nine. 10, 11, 12, 13, 14, 15, 16, 17, and 18. So there's your groups. 1, 2, 3, going down for the periods, 5, 6, 7. Now, what Shuhaib said was that, well, what about these two rows?
Isn't that 9 and 8 and 9? Well, if you look closely... It's not.
Because look at lanthium. Lanthanum. It's number 57. Okay? You see the number 57 right there? What?
It jumps to 72. That's because they didn't have enough room. That is the only reason why you have these two rows on the bottom. It's just they didn't have enough room. So technically, this is going to be 6 and this is going to be 7. So you're going to write 6 and 7 here because it's a continuation of 57 and 89 respectively. Y'all see that?
The only reason why those are down there is because it doesn't have enough room to put it in the middle. I will say another thing you need to mark, all elements after 95. Okay, so elements after, don't write it so big. 95, those are synthetic, meaning they're man-made or artificial. They're artificial. They don't exist in nature.
We made them. Now, we can make it in all sorts of ways. One of the ways we make them is we basically take atoms and collide them and combine them, and sometimes the element only exists for a nanosecond.
And then we write it on the periodic table, just to, I don't know, make us feel like we did something. because those elements don't last for more than a few seconds sometimes. Okay, so after 95, it's all synthetic.
Some of these before 95 are synthetically made, but, you know, depends. Okay? So we got what periods and groups are. Okay, now we need to know what the difference between metals and nonmetals are.
Okay, so we'll do metals and nonmetals. Metals, we'll do those first. Metals. Uh-huh. You need more, you need time?
Metals, yeah, can you see it? Okay, metals, they are shiny. And smooth.
Smooth. Some people write soft, but something smooth is better. Shiny, smooth, we know that. Okay?
They are conductors. So conductors, that means they, oops. They easily transfer. This is one reason why when you're cooking, let's say, a gumbo or whatever, you want to use a wooden spoon.
If you use a metal spoon, especially if you leave it there, the heat from the stove and from the soup or whatever you're cooking will transfer to your hand by the iron or whatever kind of metal the ladle is made out of, right? Metal transfers heat and electricity pretty well, okay? They're conductors.
They're typically cations. So they like to give away electrons. The tendency is to give away electrons.
They don't want them. They want to give away electrons. They're typically cations.
I should write typically there. You can make elements do things they don't want to do chemically. So typically they're cations.
They are ductal, which means that you can... You can slice them in very thin sheets like, think of aluminum foil, right? Very, very thin.
So ductile, you can, can be very thin, can be made into thin sheets. Think of aluminum foil. This is a good example.
They're ductile. They are malleable. I think malleable has one L.
Ooh, let me check this. I think malleable has one L. Am I going crazy?
It's like one of those words when you overthink it, then. Oh, it has two Ls. I was right.
Okay, I just went crazy there for a second. All right, so malleable, that means they can, I mean, they can bend very easily. Bend.
Easily. They don't crack, they don't just snap very easily like a cookie. You know, when you break a cookie, it just snaps. You can't just bend a cookie. You can't...
I mean, cookie dough is one thing, but once you've baked your cookie, you can't fold it into whatever shape you want, but you can do so with metal, especially if you add heat. Okay? They bend easily. Zoe, Stella... Um, I think that's all I want to go over for metals.
Uh, they're, I said shiny, right? Yeah. Oh, they're, um, at room temperature, they're solid. There are some exceptions. Notable exception.
I think there's three exceptions. Um, but the notable exception is going to be what? Y'all should know. Mercury, right?
HG Mercury. That is liquid. Liquid metal at room temperature. There's another one that, um, but that's the famous one. Okay, so these are metals.
These are the properties of metals. Okay, let's go to nonmetals. Nonmetals.
So, nonmetals, number one, are usually anions. Usually. Not always.
And they're usually like lots of gases. Okay. So it kind of depends on gases.
When they're solids, they're brittle. They are brittle. Brittle, when I think, again, I think of the cookie, right? Cookies are generally, they're just chips of hoy, and they're really, the second you bite into it, it just crumbles like crazy, right?
When you think of brittle, think of crumble. Like, it breaks really easily. Not bendable, not malleable. It's the opposite of malleable.
Brittle, so crumbles into pieces easily. Wood is brittle. Right, it's very difficult to bend wood, especially if it's dried out.
Okay, they are insulators, tend to be insulators. It's the opposite of conductor. They don't transfer electricity easily.
I was right, opposite of conductor. And then you can look back what that means. Okay, they tend to be at the right side of the periodic table.
So metals are then on the left side. With the exception of hydrogen. Metals on left. Not hydrogen, though. Not hydrogen.
Okay. This is all I want to say for non-metals for right now. Any questions about metals versus non-metals? There is an in-between. They're called the metalloids.
Metalloids have properties of both. And we'll discuss them in a second. Have properties of both.
Yes. Hydrogen is non-metal. It's the exception on the rule where left is metal, but hydrogen is the only exception there, if you don't count the metalloids.
So metalloids will have properties of both. Metalloids will have properties of both. Okay?
Now let's talk about some of these families, some of these types of metals and non-metals. The first one. Okay. It's going to be the alkali metals.
The alkali metals. These are the group one metals. I'll write that out just so.
This does not include hydrogen. You need to know that. Right? I mean, but, you know, hydrogen is its own thing.
Not hydrogen. Hydrogen is in group one, but it is not a metal. Why do they put up, why do they put hydrogen in the group 1 if it's not a metal?
Well, we'll find out in a second. Okay. But, the alkali metals are extremely reactive. They're so reactive you will never find them by themselves naturally.
You would have to separate them, forcibly separate them. Extremely reactive. What does reactive mean?
It means they like to bond to other atoms. They don't like to be by themselves. It's so reactive that it will even react with water. If you add an alkali metal to water, it will catch on fire. That's how reactive it is.
It's very dangerous. Okay, it will not last at all very long. If you were to take an alkali metal and put it out here, it will immediately react with the... Well, it's hard to see.
It'll do slower. But over time, maybe in a couple days, the outside of it will completely oxidize. Okay, you'd have to cut it to get the pure form of the metal.
Okay, and they're actually pretty easy to cut. Extremely reactive, bond to other atoms. One unique thing about all of these is that they have a valence of seven electrons. They have a valence of seven electrons. So, lithium will have seven, sodium will have seven, potassium will have seven.
Okay, they only need... Only need one electron to complete the outer shell. I'm sorry.
One. I'm sorry. They only have one valence electron. That's the second time I screwed it up today.
only have one valence electrons. That's a pattern that they have. And this is why hydrogen is included.
Because hydrogen is in group one, but not a metal. Hydrogen, not a metal, only needs... one electron to complete its shell. That's why it's put there. Yes, Liam.
Why is it like, is it just only a certain view of as well as I'm okay so far? I think all of them will like literally explode in water. Yeah.
There, yes. Yeah. Yeah, potassium, yeah, if you take pure potassium and you put it in water, it'll start fizzing.
And heat will be... What about bananas? It's bonded to something. It's never, remember, when you find potassium, it will already be bonded to something. Pure potassium...
does not exist naturally. Right? You have to separate it. Yes? Do you mean it only has one electron?
It only needs one electron to complete the shell and also all, you're right too, but remember the outer shell, the first outer shell is only two electrons. So hydrogen has one, it just needs one more to complete. Yeah, these are very dangerous when they're in their pure form. They're not at all dangerous when they're bonded to something else because they're not going to be They bonded. They already did the reaction.
Okay? When I say not at all dangerous, it depends on what they're bonded to. There are acids and bases that are very dangerous. So it depends on what it's bonded to. We'll talk about that in a second.
Okay, alkali metals. That's group one metals. Then we have the group two metals. So then you have the alkaline earth metals. Alkaline earth metals.
These are group 2 metals. Now, we don't... all you need to write is that they have... of course these are all metals, so they have all those properties that we talked about. They're reactive, but not as reactive.
But not like group 1. That's the wrong time to be doing that. They're reactive but not like group 1. The reason why they're called alkaline earth metals is that these metals are usually found in the earth's crust. And in the earth's crust.
Crust. That's why they're called the alkaline earth metals. You can find potassium and calcium and all that stuff and sodium in water and the sea and stuff like that. And not necessarily in the crust, whereas these are predominantly found in the crust.
That's why they have that extra name. So I know it's kind of confusing. You have alkaline metals and alkaline earth metals. I don't have a very good way to remember other than this.
Group one, well, it has one word, alkali. Group two has two words, alkaline earth. That's the way I remember. If you have a better way, that's great.
Some of these metals like magnesium and calcium, you know, they're in, you have to like, they're in the crust. Okay, so, you know, whereas think of sodium and potassium as being in water, not in the crust. That's another way to remember. Okay, any questions thus far? Okay, moving on from that, let's do the transition metals.
Transition metals are groups 3 through 12. There's not much to say here, but reactivity varies, right? Reactive, reactivity, or let me word that better. Some are reactive, some are not.
Some, not so much. These are industrial. A lot of industrial ones here.
So for example, nickel, cobalt, iron, titanium, tungsten. Yes. Industry, so like, you know, we build spaceships, whatever, right?
We need certain metals to do that. For instance, we need titanium, okay? I think the tip of a lot of spaceships are covered in titanium, for example. So iron, right? We use iron in all sorts of industries, right?
Very common metal. Also, the precious metals like silver, A-G is silver. A-U is gold. And some of these are pretty reactive and will rust, right? Things like nickel, iron will rust.
They react. When a metal rusts, it's reacting with air. So those are pretty reactive. But gold, for example, silver can rust. Silver can actually rust too, by the way.
Gold tends not to react. It's not impossible, it tends not to react. That's one of the reasons why humans like it, because you can buy it and you're not worried about it rusting. It will last longer than other metals because it won't bond with other stuff like oxygen.
Okay, so the reactivity varies. Any questions about the transition metals? That's through groups 3 through 12. Okay, and then we have the post transition metals. There's not much to say here. Post-transition are going to be aluminum, gallium, indium, what else, tin, thallium, lead.
Bismuth and polonium. I don't think I'm missing one. Did I get gallium in there? Yeah, okay. I do not expect you to memorize these, okay?
You just have to memorize where they are. Okay? You will be given a periodic table, and all you have to do... So let me show you a periodic table.
I'll go back. So as long as you know where the transition metals are... So I'm using my laser pointer. One second. The transitional metals cut off right here.
Okay? And then I need everyone to take this periodic table out and draw... With your pen or pencil, something dark, draw a staircase starting from boron. Draw this staircase.
That is the dividing line between metals and non-metals. Everything on the left is metal except hydrogen. And these, the ones that border, the ones that I have dotted are metalloids. So then that makes everything else.
the post transition. Okay, so draw that staircase. We're going to come back to this. The proper way to remember these is not memorizing that list, is to look at the periodic table and see what's going on.
Okay, so those are post transition. They also are considered metals. These are metals. Gosh.
And that's all we need to know. Okay. Then we have metalloids.
Metalloids are the elements that border that staircase. Border. Staircase.
Okay, and we already talked about them. They have properties of both metals and non-metals, so there's not much to say. They are often, if you had to categorize them, In terms of metal and non-metal, boron typically is treated like a non-metal, whereas germanium, silicon, and antimony are treated more like metals. But they're called metalloids for the reason they're not easily categorized.
Okay. So they border that. Let's go back to the staircase.
The way that you remember the staircase is not that, I mean, the way I do it, boron for beginning. You begin the staircase at boron, B for beginning. You begin here, and then you just do a staircase, and then you can follow that. Every single one of the ones that are underneath each step are going to be considered metalloids, except for, no, no, no, that's right, that's correct.
No, that was right. All of those are metalloids. Germanium and antimony also, okay? So let's go back here, and then now let's do, we already did nonmetals, let's just do the halogens. We got two more, guys.
Halogens. is group 17. These are non-metals. These are extremely reactive.
Especially fluorine. Especially fluorine. They're very very reactive.
They're diatomic. Meaning they like when you see them. They usually are bonded, they sometimes are bonded with each other.
So, you're going to see F2, fluorine, F2 is fluoride. You all have heard of fluoride as in toothpaste, right? Because fluoride is not as reactive as pure fluorine, okay?
Fluoride, bromide, iodide. The reason why they're called diatomic is because of that 2. Di for, you know, diameter is two radiuses. Di, it's that 2 that's kind of classified as diatomic.
The rest of the nonmetals are what we call polyatomic, but you don't need to know that. Oxygen will also combine with itself, bond with itself, same with nitrogen gas, but the halogens are all diatomic if they are just amongst each other. Okay, I need you to stop writing. for a second, I want you to just pay attention, okay?
I'm not, I want you to, I want to, I kind of want to put some puzzle pieces together. So you do not need to write this down, you just need to pay attention. It's more important that you pay attention than write anything down.
All right, let's do once again a Bohr model for lithium. I kind of want this a little bit bigger. Lithium and let's do a Bohr model for flooring. Do not write this down, you already written it down a thousand times, okay?
I want a better circle than that. Okay. And then fluorine will have two as well. Okay. We've done this before where lithium has two.
Both have a complete inner shell. Lithium has one. I'm going to put it on the side here. Fluorine will have one, two, three, four, five, six, seven.
All right. What? Look how many valence electrons each have. Well, did we learn how many valence electrons does lithium have? Valence electrons, how many does it have?
That's the valence. One. How many valence electrons does this have?
Fluorine? Seven. Okay, the valence, now the valence of lithium is seven. The valence of fluorine is one. Now, You have to understand the periodic table like a high school.
In high school, you have the popular girls, okay? Who are the popular girls in the periodic table? Who does everyone want to be like, right?
What group? Okay, flooring has a valence of one. What's the element right after flooring?
Neon. Let's look at neon for a second. In fact, I'm going to make neon neon. Look at this. Neon has 1, 2, 3, 4, 5, 6, 7, 8, 9 10. What's the valence of neon?
Zero. The valence of neon is perfect. She's happy. She's popular.
She doesn't need any more electrons. Okay? Fluorine really wants to be like neon.
That's why it's so reactive. Okay? Fluorine wants to be like neon. In fact, every atom wants to be like group 18, the noble gases.
So group 18... They're the popular girls. Everyone wants to be like them, okay?
So flooring just says, I only need one more electron. You know how there's those people, those girls that really want to be popular, and they try so hard, it backfires. They're emotionally unstable.
And then there's some people that are like, look, I'm fine. I'm confident in who I am. I don't need to be recognized and popular, right? Well, flooring is one of those desperate girls.
She really wants to be popular. That's what makes her so dangerous by herself. Okay, she really needs friends. Okay, so the idea is that fluorine is, that's one of the reasons why fluorine is so reactive. Okay, now lithium, lithium has a long way to go.
How many is she missing? Seven from her outer shell. Lithium is like, okay, I can't be popular like neon, but who can she be like? Who can she be like? She can't be like fluorine, that's too...
She can be... Oh, close! Who's another popular girl?
Not as popular as Neon, baby. Oxygen is not in the popular group. Popular group is group 18. Helium. Let's do the Bohr model for helium. Don't do it.
I'm doing it. Helium has how many? Two.
She has a complete outer shell. She's happy and popular. Lithium is like, wait, there's no way I can become like neon. That's too many electrons. But I can become like helium.
But what does lithium have to do to become like helium? This extra electron? Doesn't they don't she doesn't want it.
She wants to be like helium to be like helium She has to get rid of this electron Fluorine is like wait you want to get rid of that iron you want to be like helium? I want to be like neon. I'll take your electron Right? And there we have a bond. Okay?
So, the alkali metals and the halogens are best friends. Every alkali metal wants to give away an electron. Every halogen really wants to take an electron so they can be like the popular girls, the noble gases, group 18. Okay?
So, now here's where you write. So, halogens... Halogens...
and combined with an alkali metal, there's a special name for that. Anybody know? You've probably said it today. You probably said it yesterday. What is an element right underneath lithium?
Sodium. Sodium. What's the element underneath flooring? Chlorine.
Chlorine. Right. So if sodium and chlorine, sodium gives its electron to chlorine, chlorine really wants it.
Sodium wants to be like neon. Chlorine wants to be like argon. OK?
So then now we have sodium chloride. What is this? This is table salt.
OK? When you have an halogen plus an alkali metal, we have a name for that that's called a salt. All salts are basically halogens and alkali metals bonding. You have different types of salts. You have sea salt, which has potassium and stuff like that.
Table salt will have chlorine and sodium. Yes. Shhh. Wait, there are people over talking to you and I'm looking for them. Give me, I know maybe you would explain the material, but give me a second.
Oh, so carbon has four valence electrons, right? Carbon wants four electrons. So it will make four bonds. Right? So, how many bonds does, um...
Okay, oxygen has a little... actually let's use oxygen. Best example.
I'm gonna do it on the board up here. Because you brought up a... and we're kind of skipping ahead, so don't write this down, but it's interesting. So oxygen has how many valence electrons? Well, let me do it really fast.
Okay, it has a total of six electrons, right? So six, one, two, three, four, five, six, seven, it's eight, sorry, seven. 8. What's the valence of oxygen? 2. 2. It's missing how many?
It's missing these. Right, so it wants 2 electrons. Okay? Hydrogen has a valence of what?
You should instantly come up with these guys. One. Okay, so hydrogen wants an electron. Oxygen wants two electrons. So what happens is that they end up sharing.
So you get oxygen that shares electrons with... oxygen and then you form what is this compound? This is water. So what's going on is that oxygen and hydrogens have decided to share in order to fill their outer shell and then you get the water molecule.
Yeah. So carbon wants four so how many hydrogens will they typically want? They want four hydrogens.
Now you can have double bonds and stuff like that but yeah Yeah, so the valence, we're going to learn, valence tells you what the element might do and how many bonds it will form. Right? Yeah.
We'll develop that later in the unit. All right? Now, last one.
Oh, I already have it here. I'll just write it with you all. Okay, so we did halogens, let's do the noble gases, the popular girls. These are the noble gases.
Noble is an appropriate term. Noble, nobility, you know, they're better than everyone. They're aristocracy, they have all the money, they have all the property, they're royalty, aristocracy.
So, noble gases. Okay, are gases that are inert, non-reactive, very inert. Why aren't they reactive?
Because they got what they want. They don't need anyone. Right?
They don't want to share. They don't want to give. They've got what they want. That's why they're the noble gases.
These are odorless and colorless. You can't see them. You can't smell them. And there are trace amounts in the atmosphere. There are trace amounts in the atmosphere.
Now, because they're inert, they are very useful. You can create light, right? Humans use to create light.
Why would it be an inert matter? What? Yeah, it doesn't explode, right?
So if I have hydrogen gas and I pass heat through hydrogen gas, it will explode because it will react with the oxygen, right? That's literally how you get rocket stuff, okay? But if you pass an electrical current or heat through argon, it will not explode because it doesn't react. In fact, these light fixtures up here, I don't know exactly, I have to ask the janitors, are very likely argon. These are, usually these fixtures are argon light fixtures.
They have argon gas in them that pass electricity, it lights up, and it doesn't explode. So it's very useful lighting. When you pass different, you know, different gases will have different lightings, right?
If you pass electricity through neon, it will glow neon, right? It will glow green, okay? So, and it won't react. So valence electrons are zero.
Sorry, valence is zero. Full outer shell. Full outer shell. Okay, with that we will stop there. Well, well, let me just do the...
Let me do... This is what you're going to draw. I think the blue one's messed up. Give me a second.
A little thinner. Okay, so this is what you're going to draw or outline I should say I don't care what colors you use make sure you create Just make sure you create a key Make sure you you do a little key down here and you're good