Introduction to Chemical Bonding - Online Tutor, Practice Problems & Exam Prep

Chemical bonds are attractive forces that hold atoms together, forming molecules and compounds. Molecules consist of at least two chemically bound atoms, while compounds specifically contain at least two different elements. For example, water (H₂O) is both a molecule and a compound, whereas oxygen gas (O₂) is a molecule but not a compound. Understanding intramolecular bonds (within a molecule) and intermolecular bonds (between different molecules) is crucial for grasping chemical interactions. Chemical formulas, like C₆H₁₂O₆, efficiently represent the composition of these substances.

Introduction to Chemical Bonding

In this video, we're going to begin our introduction to chemical bonding. And so, chemical bonds are really just defined as attractive forces between atoms that hold those atoms together to form either molecules and or compounds. And so molecules is really a term that is very, very broad and refers to any substance that contains greater than or equal to 2 chemically bound atoms. Now these atoms could be of different elements or these atoms could be of the same element. And so, for example, O₂ is an example of a molecule which is oxygen gas. So, if we take a look at our image down below over here on the left-hand side, notice that we're showing you oxygen gas, which can be represented like this, or it could be represented in this format right here as well. But really, oxygen gas is when you have 2 oxygen atoms that are chemically bound to each other. And so because we have at least 2 atoms that are bound to each other, this makes oxygen gas an example of a molecule. But there are really all different types of molecules and, you can see here in this image we're showing you how oxygen gas can be taken from the atmosphere and breathe into our lungs, and we'll talk more about that process a little bit later in our course.

But now to distinguish these compounds from molecules. Now compounds, as their name implies with the "comp" part here, are a little bit more complicated and that's because they are going to have at least 2 different elements. So notice here that we're comparing the word atoms to this word elements. Molecules have at least 2 chemically bound atoms. It doesn't matter if those atoms are of the same element or if they are of different elements. Either way, if it has at least 2 chemically bound atoms then it will be a molecule, but compounds on the other hand as their name implies, they're a little bit more complicated because not all molecules are compounds, only very specific molecules are compounds, and so you can see that compounds are defined as complicated molecules themselves. So, they are molecules just a very specific type of molecule that is composed of at least 2 different elements. And so, for example, water is going to be an example of a compound, and that is because it has 2 different elements. It has the element hydrogen and it has the element oxygen. Whereas O₂ here does not have 2 different elements. It only has 2 atoms of the same element. And so, oxygen gas is not a compound even though it is a molecule, but water here is both a molecule and a compound because it meets both of these requirements here. And so, if we take a look at our image down below, you can see that we're saying that, water is an example of a compound, once again because it has 2 different elements, hydrogen element and an oxygen element. But another example of a compound is going to be this, structure right here which is a glucose molecule. Now you'll need to know about glucose later in our course, but it's good to start familiarizing yourself with this compound here.

Now, this is a compound because notice that it has at least 2 different elements. Notice that it has the element oxygen throughout, in these locations. It has the element carbon, in these locations right here, and then it also has, the element hydrogen as well. And so, this compound has at least 2 different elements and that's what makes it a compound. And glucose is really a sugar that is going to be found in many different forms of life and in many different mixtures, too, such as in honey. Now, the last idea here that you all should know is this idea of the chemical formula. The chemical formula is really what reveals both the number and the types of atoms that are in a molecule or compound. And so, an example of a chemical formula is the entire structure of glucose every single time it came out, it might take a long time to do that. And so, chemical formulas can help to write down structures much faster. So, writing down C₆H₁₂O₆ is much faster than drawing out this entire structure, so chemical formulas can be very useful in that respect. So notice that here, we're taking this compound glucose and we're changing it into a chemical formula of glucose. And so, you can see that there are a total of, this says 6 carbon atoms, so we can say this part right here means that there are a total of 6 carbon atoms. This part right here with the H₁₂ means that there are 12 hydrogen atoms right here, and then this part over here says that there are 6 oxygen atoms. So, we can fill that in right here. And so, this here is what we refer to as a chemical formula, and you'll be able to see many more examples of these as we make our way through our course. Another example would be H₂O is another, example of a chemical formula. But this here concludes our introduction to chemical bonds and how they form molecules and compounds. And moving forward, we're going to talk about many different types of chemical bonds. So I'll see you all in our next video.

Intramolecular vs. Intermolecular Bonds

In this video, we're going to distinguish between intramolecular and intermolecular bonds. Chemical bonds between atoms can either be intramolecular or intermolecular bonds. Number 1 here is focused on the intramolecular bonds, which are interactions between atoms within the same molecule. The number 1 mentioned in the text corresponds with the number 1 on the left-hand side of the image for intramolecular bonds. Let's take a look at the image on the left-hand side. Notice that in the middle, we're showing you a water molecule, we are showing you H₂O, 2 Hydrogens, 1 Oxygen atom. These lines forming between these different atoms represent a type of chemical bond that we'll discuss more as we move forward. But notice that these bonds, these chemical bonds, are forming within the same water molecule right here, and these two bonds are almost trapped within the same molecule. You can think the 'intra' can remind you of the word 'trapped', and so they're going to be trapped within the same molecule just like this example here is trapped behind bars.

Intermolecular bonds, on the other hand, are interactions between atoms of different molecules. The number 2 that we have up above in the text is going to correspond with the number 2 that we have down below in our image. Let's take a look at the right-hand side of our image this time. Here, we show two water molecules. We're showing you one over here and another water molecule over here. This time we're focused specifically on a bond that is forming between these two different molecules. Since it's forming between two different molecules, it's not going to be trapped within the same molecule, and so intermolecular bonds are not trapped. You can think that the 'ter' here cannot be used to spell 'trapped', and so it's not trapped and instead is forming between different molecules. It's almost like how you can see one person giving a high five to another person. So it's almost like one molecule is giving a high five to another molecule right here, and this high five would be this right here, forming between different molecules. You can think that 'inter' is for between different molecules.

Hopefully, this will help you better distinguish the difference between intramolecular, which are trapped within the same molecule, and intermolecular bonds, which are not trapped within the molecule and form between different molecules. We'll be able to get some practice with these ideas moving forward in our course, and I'll see you in our next video.

Appropriately label all of the chemical bonds in this image as either intramolecular or intermolecular.

Okay, everyone. Here we have our next practice problem. Appropriately label all of the chemical bonds in this image as either intramolecular or intermolecular. Alright. So we have this nice image here with these different molecules, and we have to label the chemical bonds as either intramolecular or intermolecular. Okay. So first off, let's try to remember what the difference between these two types of bonds is. Intramolecular bonds are going to be found within a molecule. And this prefix here, intra, means within. So intramolecular bonds are going to be bonds between atoms within a molecule. Okay. Intra means within. Intermolecular bonds are going to be different. Inter, this prefix here, means between. So realize that intramolecular tells you about bonds within the molecule. Inter means between the molecules. So, we have intermolecular bonds between different molecules. Okay. So, now we have these different molecules. So this is 1 molecule, this is 1 molecule, and this is 1 molecule. And these molecules are going to be H2S. Don't worry about knowing that right now. But if you're wondering, they are called hydrogen sulfide molecules. And the two hydrogens and a single sulfur is one molecule. Okay? Alright. So now you can tell that we technically have 3 of these hydrogen sulfide molecules. And we're going to see that the solid lines are going to be the bonds between atoms of the same molecule. So what does that mean? That means that they should be intramolecular. I'm going to highlight them in green. So these bonds between the sulfide or the sulfur and the hydrogen are going to be within a single molecule, and those are going to be the intramolecular bonds. Now, generally speaking, intermolecular bonds are commonly drawn as dashed lines while intramolecular bonds are generally going to be drawn as solid lines. So you can see that we have 3 molecules of hydrogen sulfide, and you're going to see that they are going to be interacting. And we can see that these bonds that I'm highlighting in blue are going to be the intermolecular bonds. So these ones here are the intermolecular bonds in blue, and these ones here in green are the intramolecular bonds. Okay. Just to recap, intermolecular is between the molecules and intramolecular is between the atoms of the same molecule. Okay, everyone. Let's move on to our next video.

Map of the Lesson on Chemical Bonding

Hey, guys. In this video, we're going to talk about this image that we have down below right here, which is actually a map of our lesson on chemical bonding. And so notice at the very top here we have chemical bonds, and all of these things that are down below are really just different types of chemical bonds that we're going to be mentioning in our course moving forward. And so again, this image is really a map because you can use it like a map to make predictions about where we're headed, where we're going next in our lesson. And so here's how the map works. We're going to start at the top talking about chemical bonds but then we'll always explore the leftmost branches first. So we'll talk about covalent chemical bonds, that's what you should expect the next lesson will be about. After we talk about covalent chemical bonds, we'll continue in our lesson talking about non-polar covalent bonds. After we've explored the leftmost branches, then we'll start to zoom out and explore right branches. So we'll talk about polar covalent bonds and then, of course, once we've explored all those, we'll continue to explore the leftmost branches first in this order that you see here. So really, this is a map of our lesson. And really what you'll see is that chemical bonds can really be broken up into 2 major categories, covalent chemical bonds, which include nonpolar covalent bonds and polar covalent bonds. And then we also have chemical bonds that are noncovalent. And noncovalent chemical bonds include strong electrostatic interactions like this strong guy over here in the electrocution symbol. And noncovalent interactions also include weak Van Der Waals interactions like this weak little guy over here. And so moving forward in our course, we're not going to talk a lot about the weak Van Der Waals interactions. You'll learn more about those weak Van Der Waals interactions in a chemistry course. But for our biology course, we're going to focus most of our attention on these colored boxes, the covalent and the noncovalent, but the ones that are strong electrostatic interactions, which include the ionic bonds and the hydrogen bonds. Now, once again, moving forward, we're going to talk about each of these different types of bonds in their own separate video and you can use this image as a map to figure out what we're going to talk about next. So once again, in our next video, you should expect that we're going to talk about covalent chemical bonds. So I'll see you all in that next lesson video.

Map of the Lesson on Chemical Bonding

According to the map above, which of the following are types of covalent bonds?

a) Polar.

b) Van der Waals.

c) Ionic.

d) Hydrogen.

e) None of the above.

• A. Polar
• B. Van der Waals.
• C. Ionic.
• D. Hydrogen.
• E. None of the above.

Here’s what students ask on this topic:

What is the difference between a molecule and a compound?

A molecule is a substance that contains at least two chemically bound atoms, which can be of the same or different elements. For example, O₂ (oxygen gas) is a molecule consisting of two oxygen atoms. A compound, on the other hand, is a specific type of molecule that contains at least two different elements. For instance, H₂O (water) is both a molecule and a compound because it contains hydrogen and oxygen atoms. Therefore, while all compounds are molecules, not all molecules are compounds.

What are intramolecular and intermolecular bonds?

Intramolecular bonds are interactions between atoms within the same molecule. For example, the bonds between hydrogen and oxygen atoms in a water molecule (H₂O) are intramolecular bonds. Intermolecular bonds, on the other hand, are interactions between atoms of different molecules. An example is the hydrogen bond between two water molecules. Intramolecular bonds are generally stronger than intermolecular bonds, which are crucial for determining the physical properties of substances.

What is a chemical formula and why is it important?

A chemical formula represents the number and type of atoms in a molecule or compound. For example, the chemical formula for glucose is C₆H₁₂O₆, indicating it contains 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. Chemical formulas are important because they provide a concise way to convey complex molecular structures, making it easier to understand and communicate the composition of substances in chemistry.

What are the different types of chemical bonds?

Chemical bonds can be broadly categorized into covalent and noncovalent bonds. Covalent bonds involve the sharing of electrons between atoms and can be further divided into nonpolar covalent bonds (equal sharing of electrons) and polar covalent bonds (unequal sharing of electrons). Noncovalent bonds include strong electrostatic interactions like ionic bonds and hydrogen bonds, as well as weak Van der Waals interactions. Each type of bond plays a crucial role in the structure and function of molecules and compounds.

How do you distinguish between polar and nonpolar covalent bonds?

Polar covalent bonds occur when electrons are shared unequally between atoms, resulting in a partial positive charge on one atom and a partial negative charge on the other. This usually happens when the atoms involved have different electronegativities. An example is the bond between hydrogen and oxygen in water (H₂O). Nonpolar covalent bonds, on the other hand, involve equal sharing of electrons between atoms, typically of the same element or similar electronegativity, such as the bond between two hydrogen atoms in H₂.