The easiest way to learn that is just to look at some examples. So what I wanna do first is just go through these 6 examples, and then I'm gonna show you the difference between Bronsted, Lowry, and Lewis. Okay? So let's look at a. First of all, a is water and water, I already told you, was an exception. What that means is that it can really do anything it wants depending on what the other reagent is. So remember that it has electrons here. It has a lone pair there, a lone pair there, and it also has protons. So what that means is that it it can act as a Lewis acid, meaning it can be an electron pair acceptor. K. Because it can give away a proton, make way for an electron pair. It can also be an electron pair donor, meaning it can give away one of its lone pairs. It can also be a Bronsted Lowry acid, meaning can give away a proton, and it can also be a Bronsted Lowry base, meaning that it can donate that means that it can accept a proton. So it can do all of these things. So just think whenever you see water, all of the above. It could do whatever. Now we're gonna go to a more specific reagent that doesn't do all of these things. In fact, it's only gonna do one of them. Okay? This is boron and if you guys remember from my talk on I told you guys about the octet rule. How many electrons does boron want to have in its octet? It wants to have only 6. K. Six electrons. Okay? And what that means is that it actually prefers to have 3 bonds and 6 electrons. It's happy the way it is, but what that means is that it's always gonna have one empty orbital and that orbital is a p orbital. So boron always has an empty p orbital. The reason I'm teaching you this is because it seems kind of specific, but this comes up a lot in organic chemistry 1. So I want you guys to remember that boron's kinda special. It always has that empty p orbital. There's actually another atom that's very similar and that's the one right under it in the periodic table, and that's aluminum. Aluminum also has an empty p orbital and then 3 bonds. Is that cool so far? That empty orbital, turns out since it's empty, it can accept electrons really, really well. Okay? But it's not a good proton donor. The reason is because if gave away a proton, it would break its octet and then it would only have 4 electrons. Okay? So what that means is that is this gonna be an electron pair acceptor? Yes. If I say electron pair acceptor, which of these 4 is that? Look at my definitions above. Which one is the electron pair acceptor? Lewis acid. So it turns out that BH3 is a really good Lewis acid. Okay? But now let's see, is it also a Bronsted Lowry acid, which means is it a good proton donor? No. It sucks. It actually is terrible. So it is not a Bronsted Lowry acid but it is a Lewis acid. Isn't that interesting? So this is an example where the 2 definitions don't line up exactly. Okay? Now let's talk about the base part really quick. Is it a good Lewis base, meaning does it give away electrons? Obviously not. It doesn't have any electrons. So no. And then is it good at accepting protons? Also no. Okay? So what that means is that it's only one of these things, which is that it's a Lewis acid. Okay? Now I want you to hold on to that but just keep in mind that this is different from water. How water was a good Lewis acid and Bronsted Lowry, which is like I said, about 90% of the molecules we encounter have both of them agreeing with each other. But then there are some special molecules like these guys that only do one of them. Alright? So now let's look at these other ones. This is a molecule c. It's a molecule that I've introduced to you guys before. It's called pyridine. Okay. And it has a lone pair here. Okay. So is it gonna be a good electron pair acceptor? No. If it accepted another lone pair, that would break its octet. Right? So no, it's not a good electron pair acceptor. Is it a good electron pair donor? Yeah. Because it has a free lone pair just hanging out here. So it is a good electron pair donor. It's a good nucleophile or we'd say a Lewis base. K? Is it a good Bronsted acid, meaning that it can donate protons? Okay. Is it a good Bronsted base, meaning that it can accept protons pretty well? Actually, it can. So this would be both one of those examples where it's both a Lewis and a Bronsted base. Okay? So I just want you guys to keep that in mind. These agree with each other because it can donate electrons but it can also accept a proton. Okay? Now let's look at this next one. So I'm gonna go through these a little quicker, but basically now I have, basically lone pairs on this o and what I want to know is that could that oxygen there be a Lewis acid? Could it be an electron pair acceptor? Actually it could if it gave away this proton. If it gives away the proton, then it could accept 2 electrons. So it actually is a Lewis acid. Is it a good Lewis base, meaning that it's good at giving away electrons? Not really. Okay. Is it a good Bronsted acid, meaning that good at giving away protons? Actually, yeah. We just said that it can give away this proton. So it's a Bronsted acid. Is it a good Bronsted base, meaning that it can accept protons. No. Not really. Okay? Now you might be wondering, Johnny, how did you know that this was gonna be a good acid and give away that proton? Well think about the functional group. This is called XHTML Accessible Academyarmyilic acid. Okay. If you forgot that, remember that basically COOH is XHTML Accessible carousel acid. So what that means is that it has a very acidic h, so it's easy to give that h away. And if it's giving the h away, then what is it doing? It's gonna accept a lone pair. Okay? Now let's talk about this next one, a double bond. Is a double bond a good electron pair acceptor? So let's say I have an electron pair and now it's gonna try to go into that double bond. No. That would be terrible. That would break the octets of 2 carbons. Okay. Is it a good electron pair donor? Okay. And actually, yes it is because remember that I said that these electrons can donate to something else. I can move those electrons to some kind of electrophile. So this is actually a really good Lewis base. Okay? Is it a Bronsted acid, meaning that it can donate protons? Don't. Not at all. It's not an acid at all. Is it a good Bronsted base, meaning that it's easy for it to to, to accept protons? And actually, no, it's not. This is not a good example of a Bronsted base because once again, I would be basically breaking an octet to accept a proton. Okay? So this is gonna be one of those examples where this is gonna be mostly a Lewis base and it's not gonna be a Bronsted base very much. Okay? It's gonna act more like a Lewis base because it's gonna be really good at giving away the electrons. Okay? But it's not very good in its normal state. It's not good at accepting it's accepting protons. Okay? So then we finally have this last one, which is just, an alkane. Okay? An alkane, this one is unreactive. It doesn't have anything to react. Remember that we talked about reactivities before and we talked about how you need a double bond, you need a dipole, you need, you know, a charge, some strain. None of that. So this is just not gonna be anything. It's not gonna be good at donating protons and it's also not gonna be good at accepting them. Just it's not gonna do anything because it's unreactive. Okay? So in all these cases, I was looking for a reactive site. All of these had a reactive site except this last one.