Covalent Bonds - Video Tutorials & Practice Problems
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1
concept
Covalent Bonds
Video duration:
4m
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Video transcript
in this video, we're going to begin our lesson on co violent bonds and so co Valent bonds are really just defined as an interaction between two atoms that results from the sharing of electrons. And so, really, in this context, here, you can think that the word co Vaillant just means sharing of electrons. And so if electrons are being shared between two different atoms, then we have ourselves a co Vaillant bond. Now the thing is that electrons that are being shared between atoms can be shared in two different ways, and this leads to two different types of Covalin bonds that share the electrons in different ways. The first type of Covalin bond that you all should know is the non polar Covalin Bond. And then the second type of Covalin bond that you all should know is the polar Covalin bond. Now, later, in our course in a different video, we'll talk more about the differences between non polar Covalin bonds and polar Covalin bonds. But for now, what I want you guys to know is that the reason that there are two different types of co violent bonds is because the two types of Covalin bonds exist due to differences in Adam's electro negativity ease and so electro negativity is really just defined as a measure oven Adams attraction to electrons. Or, in other words, it's a measure of how hard Adams pull on electrons, and so electro negativity is really scaled from zero all the way up to four at its maximum. So an electro negativity of zero means that an atom is not very electro negative at all. And that means that it does not pull hard on electrons, whereas an electro negativity value that's closer to four means that the atom is very electro negative and that it pulls really, really, really hard on electrons. So that's important to keep in mind about electro negativity. Now, when we take a look at a periodic table, what you'll notice is that the atoms are arranged based on their electro negativity values, and so you can see that as we go from the left hand side to the right hand side of the periodic table. Uh, there is increasing. There are increasing values of electro negativity is so within these tables. You can see that underneath. We're showing you these numbers, and these numbers here represent the electro negativity values of these atoms, and so you can see that as you start from the left and make your way to the right. Adams become mawr electro negative, but also noticed that Adams also increased in electric negativity from bottom to top. So if you pick any column notice if you start at the bottom and make your way to the top, the atoms become Mawr and Mawr electro negative. And so that's important to note that the electro negativity is really what is the reason for these two different types of Covalin bonds that we're going to talk more about moving forward Now there's no need to have to memorize all of these electro negativity values. That's something that you're likely not going to need to know. But what you should be able to recognize is that oxygen is one of the most electro negative atoms that exist. In fact, the Onley Adam that is mawr electro negative than an oxygen atom is flooring, and so this is important to keep in mind, especially when we start to talk about the water molecule later. In our course, which we know water molecules have one oxygen atom, so that's important to keep in mind. Oxygen is very electro negative, and it pulls really, really hard on electrons for that reason. So this here concludes our introduction to Covalin Bonds and again moving forward. In our course, we'll talk more about non polar and polar Covalin bonds, so I'll see you all in our next video.
2
Problem
Problem
When two atoms share a pair of electrons, the bonding is referred to as:
a) Ionic.
b) Covalent.
c) Unstable.
d) Hydrogen.
e) Polar.
A
Ionic.
B
Covalent.
C
Unstable.
D
Hydrogen.
E
Polar.
3
concept
Nonpolar Covalent Bonds
Video duration:
5m
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Video transcript
Now from our last lesson video. We know that there are two types of Covalin bonds that exist due to differences in Adam's electro negativity ease or how hard Adams pull on electrons. And so in this video, we're going to talk about the first type of Covalin bond, which is the non polar Covalin bond. Now, as we mentioned in our last lesson video, the word Co valence here means sharing of electrons. And so even in non polar co violent bonds, there's going to be some sharing of electrons. Now. The word non polar here is really referring to the equal sharing of electrons between atoms. And so non polar covalin bonds are described by equal sharing of electrons between atoms. Now the reason that the electrons are being shared equally in non polar Covalin bonds is because the two atoms have similar electro negativity ease, or they pull very similarly on the electrons. And so if we take a look at our example image down below of non Polar co. Vaillant bonds, which will see is we've got a little image here of two people sharing the electrons very, very equally, and so you can imagine that hydrogen gas, which is molecular formula, is H two eyes going to be two hydrogen atoms as we see right here, that air forming a co violent bond and they're sharing electrons on. You can see that down below as well that these two electrons right here are being shared between these two hydrogen atoms. Now, the hydrogen atoms have identical electro negativity ease because they are the same Adam. And that means that the two hydrogen atoms pull exactly the same on these two electrons that are being shared. And so because they both pull exactly the same on those two electrons, they're going to share these two electrons really, really equally. And so that means that this bond that forms between these two hydrogen is going to be a non polar Covalin bond. Equal sharing of electrons between these atoms. Now very similarly over here in the middle, what we have is oxygen gas, which we know it's chemical formulas 02 And so it's going to be two oxygen atoms that are forming bonds between each other. And each of these lines represents the sharing of a pair of electrons. And so when we take a look down below right here. Notice that there are two pairs of electrons being shared, which is why it forms this double bond right here. Whereas over here there's only one pair of electrons being shared. So that's why it only forms a single bond. One bond. Now the two oxygen atoms. Because they are of the same element, they have the exact same electro negativity, which means that the two oxygen's are pulling on those shared electrons exactly the same. And so once again, these two pairs of electrons that are being shared between these two atoms are gonna be shared equally between the two atoms. And that's why these bonds here for me between the two oxygen's are gonna be non polar Covalin bonds. Equal sharing of electrons between these atoms now s so far what we've looked at our bonds between atoms that are identical. But non polar bonds can also form between bond between atoms that are not identical. For example, this image over here. So notice that we're showing you a carbon atom forming bonds with four hydrogen atoms. Now, the thing is, is that carbon and hydrogen have very, very similar electro negativity is they're not identical, but they're very, very similar. And what this means is that they're going to pull on the electrons very, very similarly. And so that means that each of these bonds that you see here, which represents ah pair of electrons being shared, is going to be shared equally between the carbon atom and each of the hydrogen atoms. And so because once again there is equal sharing of electrons, these air going to be non polar co violent bonds and the molecular formula of this molecule ch four. But the common name for it is methane. And so that's another classic example of non polar covalin bonds. Now, over here on the right, what we have is a little image to help remind you that non polar co Valent bonds is due to equal sharing of electrons. So this little symbol that you see right here is a symbol that represents electrons. And so you can see that we've got two people or two Adams, if you will, that air sharing this electron and pulling on the electron almost like a tug of war match. And so because these two people are of the same size, they're going to pull on the electron pretty equally. They're gonna pull on it about the same. And so the electron is going to remain pretty much right in the middle here, and they're gonna be sharing the electrons equally. And that is exactly what non polar Covalin Bonds. That's how they're characterized. And so now that we've introduced non polar Covalin Bonds will be able to get a little bit of practice in our next video. And then we'll talk about polar Covalin Bonds, so I'll see you all in our next video.
4
Problem
Problem
What makes a covalent bond nonpolar?
a) The bonded atoms share electrons unequally.
b) The bonded atoms share electrons equally.
c) The bonded atoms have equal electronegativities.
d) The bonded atoms have unequal electronegativities.
e) a and d only.
f) b and c only.
A
The bonded atoms share electrons unequally.
B
The bonded atoms share electrons equally.
C
The bonded atoms have equal electronegativities.
D
The bonded atoms have unequal electronegativities.
E
a and d only.
F
b and c only.
5
concept
Polar Covalent Bonds
Video duration:
6m
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Video transcript
So now that we've introduced non polar Covalin bonds in our previous lesson videos and this video, we're going to introduced the second type of co violent bond, which is the polar co violent bond. Now, once again, the word koval it here means the sharing of electrons. And so, even in polar co Vaillant Bonds there's going to be sharing of electrons. But the word polar here is really referring to the unequal sharing of electrons between atoms. And so polar Covalin bonds are characterized by unequal sharing of electrons. Now, the reason that the electrons are being shared unequally and polar Covalin bonds is due to different electro negativity is between the atoms. And so what this means is that they're going to pull on the electrons with different amounts of strength. Now, of course, unequal sharing of electrons between atoms is going to lead to an unequal distribution of these negatively charged electrons, and unequal distribution of negatively charged electrons is going to lead to partial charges. And so this symbol right here is the Greek symbol delta, which can be used to symbolize for the word partial, and so you'll see this symbol down below throughout our image. So in our image over here on the left hand side, we're showing you a few examples of polar co Vaillant Bonds. And so the first example that we're showing you is hydrogen chloride whose chemical formula is H C L. So you could see the hydrogen atom over here and the chloride Adam over here Now, hydrogen and chloride have very different electro negativity. Ease chloride polls really, really hard on electrons. It has a high electro negativity, but hydrogen does not pull very hard on electrons. It has a low electro negativity. So there is a big difference here. And the electro negativity is between these two atoms. And so what that means is that this bond that forms between them, which represents the sharing of two electrons, a pair of electrons. Because chlorine pulls harder on these two electrons, these two electrons are going to spend mawr time with the chlorine. And remember, the electrons are negatively charged. So because these two negatively charged electrons spend more time with the chlorine because the chlorine pulls harder on these electrons because it's more electro negative. Uh, the chlorine is gonna be associated with a partial negative charge because once again it's pulling these negatively charged electrons harder, and so they spend more time with the chlorine. And that's what gives the chlorine a partial negative charge. And the opposite happens to the hydrogen. The hydrogen does not pull as hard on the electrons because it is not as electro negative. And so it has these electrons for less amount of time. And so if you give up something that's negative, you therefore become more positive. And so it gets, Ah, partial positive charge. And so you can see how this unequal distribution of electrons between the atoms leads to partial charges. Now we can see something very, very similar if we take a look at a typical water molecules such as H, which is Who's chemical formulas H two up. It has two hydrogen atoms and one oxygen atom. Now, once again, oxygen is one of the most electro negative atoms that exists. It is super electro negative, which means that it pulls on these electrons super super hard. The hydrogen atoms, on the other hand, once again, are not very electro negative, so they do not pull on electrons that hard at all, and so Of course, each of these lines that we see here represent a pair of electrons being shared between the atoms so you can see down below. We have a pair over here and a pair over here being shared. And so because once again, oxygen pulls really, really hard on these electrons that are being shared, those electrons are going to spend more time with the oxygen. And because the electrons are negatively charged, it gives the oxygen a partial negative charge on it. And once again, the hydrogen, on the other hand, are gonna have partial positive charges. And this occurs on every single water molecule, uh, that exists here. Now. The last example that we have of polar Covalin bonds is ammonia, whose chemical formula is N H three. And once again you could see it has one nitrogen atom and three hydrogen atoms. The nitrogen atom is going to be much more electro negative than the hydrogen atoms, which are not very electro negative. And so this means that the nitrogen atom is going to pull harder on the electrons. There's a different electro negativity is once again. And so, uh, these electrons that are being shared here and here and here are going to spend more time with the nitrogen atom. And that gives the nitrogen atom a partial negative charge. And once again, the hydrogen zehr going to have partial positive charges. And so again, the main take away here is that polar Covalin bonds are due to unequal sharing of electrons and unequal sharing of electrons means that the distribution of electrons is going to be unequal is well, which leads to partial charges. And so over here on the far right, what we have is another image to help, uh, clear up this idea of polar Covalin bonds. So basically, you can think in polar Covalin bond because they are sharing electrons, but they're sharing them unequally. There's pretty much a bully here in this tug of war battle on the electrons. And there's gonna be one Adam that is much more electro negative than another Adam. That does not pull very hard on electron. So the electron that's being shared is going to spend mawr time with the Mawr electro negative, Adam, and that creates a partial negative charge and the atom that is kind of deprived of the negatively charged electron becomes slightly positively charged, partially positively charged. And so this all results from unequal sharing of this electron. And that's why you can see that the electron is closer to the more electro negative Adam, because it pulls harder on it. And so this year concludes our introduction to Polar Covalin bonds, and we'll be able to get some practice moving forward in our course, so I'll see you all in our next video.
6
Problem
Problem
If a covalent bond is polar:
a) Electrons are not shared by atoms.
b) Protons are shared by atoms.
c) The bond is not important to living cells.
d) One of the atoms has a partial negative charge.
e) The bond is not a strong bond.
A
Electrons are not shared by atoms.
B
Protons are shared by atoms.
C
The bond is not important to living cells.
D
One of the atoms has a partial negative charge.
E
The bond is not a strong bond.
7
Problem
Problem
Bonds between two atoms that are equally or similarly electronegative are ________.
A
Polar covalent bonds
B
Nonpolar covalent bonds
C
Intermolecular bonds
D
None of the above
8
Problem
Problem
The hydrogens and oxygen of a water molecule are held together by ______ bonds.