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General Chemistry

Learn the toughest concepts covered in Chemistry with step-by-step video tutorials and practice problems by world-class tutors

23. Chemistry of the Nonmetals

Hydrogen Atom

Hydrogen Chemistry

Although hydrogen represents the simplest element on the Periodic Table, it is by the far most abundant element in the universe. 


Atomic hydrogen possesses only 1 proton and electron based on its atomic mass and atomic number. 


The Composition and Chemistry of Hydrogen

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Hey, guys, In this new video, we're gonna take a look at the chemistry behind the hydrogen atom. Now, before we start, we should realize here is that when it comes to abundance, hydrogen is the most abundant element that we have in the universe. In fact, nearly 90% of all elements in the universe is just hydrogen. Now on Earth, the most common form of hydrogen is H two gas. But the thing is, H two gas represents the lightest gas out there. And because of Earth's low gravity, we don't find very much of it just within our normal environment. Now we're gonna say here the hydrogen atom represents the simplest of the elements of the periodic table. So remember, hydrogen has an atomic mass of one and an atomic number of one. Remember, if we subtract these, that gives us a number of neutrons. So hydrogen has zero neutrons because it's atomic numbers. One. It has one proton because it's neutral. It also has the same number of electrons, so it also has one electron. So I have one and one. Now, remember, hydrogen also has two other isotopes that are natural as well. There's deuterium and deuterium will usually designated with the letter D here. It has one neutron in it. So now the atomic masses to atomic numbers. Still one. So we have one proton now. And actually, we have one neutron. We subtract those first. We have one proton, and we have one electron. Also remember, the other form that hydrogen could take is tricky. Um, which we represent. What? The letter T. This has two neutrons in it. So the atomic masses now three. So we have two neutrons, one proton, one electron. Now, hydrogen is the most abundant of all three of these isotopes. But it's important. Remember about deuterium and treaty. Um, those of you later on decided to go into organic chemistry. You'll learn more about the other two isotopes in greater detail. But for right now, just realize that hydrogen has three natural occurring isotopes, hydrogen normal deuterium and tritium. Now here, we're gonna say that elemental hydrogen will react with elements to form either Ionic or Covalin Hydroids. Now, what we need to realize is we're gonna say it forms Ionic hydroids one connected to yes, boron for medals. In this case, it's gonna represent the hydride ion. So it'll be a church minus, which is our hydride ion interacting with boron or those medals hydride Because here hydrogen has one electron. Normally it gets a negative one charge because it gained another electron. We can also say that it represents a covalin hydride. This naturally occurs when we're dealing with hydrogen when connected to non metals. Now, if we take a look here at the Ionic Hydride, we're going to stay here when reacting with Group One A elements the heavy group to a elements off calcium, strong Thiam and burial and other reactive metals that we'll talk later on. This is when we make ionic hydrates. Now we're gonna say these compounds tend to be white, crystalline, solid, so they exist as solids within our environment. Now, of course, if you took that solid and dumped it into water, it would break up in tow ions. Now here we're going to say we're reacting. Case solid. So potassium solid with hydrogen gas. Now, how do we figure out what the product is gonna look like, which is have to recall what are the charges of these elements when they're next to each other? Potassium is in Group one? A. So naturally it'll be plus one. Now, remember, hydrogen, when it's with a boron or medals, it doesn't have an H plus charge. It has an H minus charge. So one is +11 is minus one. Remember, when the numbers are the same, they just cancel out and the two ions combined together. So this would just be kh solid. Then we just simply need to balance it. We have to potassium and two hydrogen on the react inside. So we throw it to here. So this would represent potassium hydride for the next one. Same type of idea we're gonna say here barium is in group two way. So it's natural charges plus two hydrogen again when it's connected to metals is minus one. Now, when the numbers are different, we don't cancel them out. They crisscross. So the two from here comes here. The one from here comes here. So we wind up getting is B A H two solid. So this becomes barium hydride. So just remember here again, when it's connected to metals, it'll have minus one when it's connected to boron, also minus one. Now the hydride ions. So H minus can also react as a blank agent and donate its electrons. So we just have to remember. What does this mean? If you're donating your electrons, that means you're losing the electrons, Which means that hydride is being oxidized. And if it's being oxidized, what kind of agent is it? It would be a reducing agent. Now, if you find this a little bit tricky, remember, go back to our reviews when it covered oxidation reduction reactions. Remember, if you're oxidized, you're the reducing agent. Also, we can say hydride ion also serves as a strong base. This was talked about in this section dealing with electrolytes that I covered, as well as a section dealing with acids and bases. Remember, hydride ions is one of the strong ions to make a strong base. Now, here, how does it work when we're reacting it with these Now, guys, we're gonna work these questions out, so let me take myself out of the image. So here for this example here we have silicon with three bro means as a liquid. Plus we have sodium hydride. Now what happens here in this example is we have an A plus which is in group one A. And we have br minus minus one because it's in group seven A. Their numbers are the same. They just have opposite charges. So when they combine, they just cancel out the charges. So we have any BR here. It's not going to be in an aqueous solution, so we're gonna make a solid here. Plus now, what's happening here is this silicon here is connected to the halogen, but the halogen have left to connect with the sodium. So now silicon is just a solid here. Then that leaves hydrogen all by itself. Now, if hydrogen is not gonna be, ah, charged ion, it's gonna exist in its natural form, which is just hte too. And H tour is a gas. All we have to do now is balance. Things we have to hydrogen is here, but only one here. So we put it to Now we have to sodium here, but we only have what we only have one here. Now we're gonna run into some issues when we're trying to balance this out because there are three bro means here. So if I put it to here, it's not enough, bro means So what I'll do instead is I'll put a six here, which means I'll have a six here. I'll put her to hear Ah, three here and a two here. You have to make sure things are balanced out here on this side. We have to silicon like we do here. We have two times 36 BRS like we do here. We have six sodium and six hydrogen, so now it's balanced. Now, in this case, it's acting as a strong reducing agent. Okay, so here it's acting as a strong reducing agent. It's being oxidized in the process, because here it was minus one and here now becomes zero for its oxidation number. So in this first example, H minus is acting as a reducing agent again. Go back and review redox reactions. If you're not familiar with this concept now here HCL with any NH HCL is a strong acid, and then NH here is acting as a strong base. So what happens here is this c l minus, and this n a plus combined to give me an a C. L here, since one is acting as an acid, the other ones acting as a base we're gonna Macon acquis ionic compound. So here, this is a base here. This is an acid. Now the H plus of the acid will combine with the H minus of the base. They will combine together to give the H two, which serves as a gas. So in this case, the H minus, as a reacting, is serving as a strong base. Okay, so in the first example, H minus was acting as a strong reducing agent in this second example is acting as a strong base. Now, finally, here we have a co violent hydroids. This is when it's reacting with non metals. Ah, very important one to realize here is we have hte two plus end to gives us an H three. So we have hydrogen gas, reacts with nitrogen gas to create two moles of ammonia. Now we could say a couple things about this reaction. Remember, I've seen this reaction before. I've talked about it with you guys in later earlier lessons. We say that this is a process that's incredibly important because it's one of the processes to help us make fertilizer. Without this process, without fertilizer, we wouldn't be able to grow as many crops as we need to to feed populations, so it serves a very big important role in everyday life. Also, Weaken. Say here that it has a Delta H value. Remember, Delta H is your envelop. It's a very negative entropy, Very large number negative, 91.8 killer jewels. So that means that this is highly exo, thermic, highly exile. Thermic, which means it releases a lot of heat, and in fact, we'll see with other types of reactions. When it comes to hydrogen, our water, a lot of heat is released when it reacts with certain metals from the periodic table. A lot of these reactions are highly eggs, a thermic exile. Thermic reactions release a ton of energy, a ton of heat into the environment because they're trying to make themselves more stable by releasing excess heat and energy. Now hydrogen maybe a simple element. But when it comes to reactions, there's a lot of different things that it can do. So just realize here that it could exist as an H plus ion when which is called the hydro knee my on or it can exist as an H minus ion, which is your hydride ion or it could exist as H two gas. It reacts with different elements in the periodic table to produce different results. So make sure you go over the fine points that we talked about here when it comes to this simple element.