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

Chemical bonding involves attractive forces between atoms, 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 only a molecule. Bonds can be intramolecular, occurring within a molecule, or intermolecular, occurring between different molecules. Understanding these concepts is crucial for exploring various types of chemical bonds, including covalent and ionic bonds, which play significant roles in biological systems.

Introduction to Chemical Bonding

In this video, we're going to begin our introduction to chemical bonding. Chemical bonds are defined as attractive forces between atoms that hold those atoms together to form either molecules or compounds. The term "molecules" is very broad and refers to any substance that contains greater than or equal to 2 chemically bound atoms. These atoms could be of different elements or could be of the same element. For example, O₂ is an example of a molecule which is oxygen gas. If we take a look at our image on the left-hand side, notice that we're showing you oxygen gas which can be represented in different formats. Oxygen gas occurs when you have 2 oxygen atoms that are chemically bound to each other. Since there are at least 2 atoms that are bound to each other, this makes oxygen gas an example of a molecule. There are all different types of molecules, and as shown in this image, you can see how oxygen gas is taken from the atmosphere and breathed into our lungs. We'll talk more about that process later in our course.

To distinguish these compounds from molecules, it's important to note that compounds, as their name implies with the "comp" part here, are a bit more complicated. This is because they have at least 2 different elements. Molecules have at least 2 chemically bound atoms. It doesn't matter if those atoms are of the same element or if they're of different elements. If it has at least 2 chemically bound atoms then it will be a molecule. Compounds, on the other hand are a specific type of molecule composed of at least 2 different elements. For example, water is an example of a compound because it includes the elements hydrogen and oxygen, whereas O₂ does not have 2 different elements, it only has 2 atoms of the same element. So, oxygen gas is not a compound even though it is a molecule; but water is both a molecule and a compound because it meets both of these requirements.

Another example of a compound is glucose. You'll need to know about glucose later in our course but it's good to start familiarizing yourself with this compound here. Glucose is a compound because it has elements like oxygen, carbon, and hydrogen distributed throughout its structure. This compound has at least 2 different elements, which qualifies it as a compound. Glucose is a sugar found in many forms of life and mixtures, such as in honey.

The last idea you should know is the concept of the chemical formula, which reveals both the number and type of atoms in a molecule or compound. An example of a chemical formula is C₆H₁₂O₆, which is the chemical formula for glucose. Writing down C₆H₁₂O₆ is much faster than drawing out its entire structure. Chemical formulas are extremely useful for quickly reporting the structures of compounds. Notice that the glucose chemical formula indicates that there are 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. Another example of a chemical formula is H₂O, which is the chemical formula for water. This concludes our introduction to chemical bonds and how they form molecules and compounds. Moving forward, we'll discuss many different types of chemical bonds. I'll see you all in our next video.

Intramolecular vs. Intermolecular Bonds

In this video, we're going to differentiate between intramolecular bonds and intermolecular bonds. The bonds between atoms can either be intramolecular or intermolecular. The intramolecular bonds are interactions between atoms that are within the same molecule. If we take a look at our image down below on the left-hand side, notice we're showing you a water molecule, H₂O, with 2 hydrogen atoms and 1 oxygen atom. Notice that between these atoms, we are showing you these bonds. Now, we'll talk about the names of these specific bonds later in our course, but for now, notice that these bonds are within the same water molecule. Because they are within the same molecule, these are intramolecular bonds. You can think of intramolecular bonds as being trapped within the same molecule. The prefix 'intra-' can remind you of 'entrapped,' as these bonds are trapped within the same molecule, much like how this person is trapped behind these bars.

Now, the intermolecular bonds, on the other hand, are interactions between atoms of different molecules. If we take a look at our image down below on the right-hand side, notice that we're showing you two different water molecules. We're showing you one water molecule here and a second water molecule here. Notice that the bond that we are looking at specifically is the bond going between the two different molecules. Because this interaction is between different molecules, this interaction is an intermolecular bond. You can almost think of it as one molecule giving the other a high five, similar to how one character here is giving a high five to another at this spot. This green area here represents the intermolecular bond. Notice that 'inter-' does not include 'tra' and so it cannot spell 'entrapped,' indicating that it is not trapped within the same molecule; instead, it spans between two different molecules. Once again, we can say that the intermolecular bond is between two molecules rather than within one.

Hopefully, this helps you differentiate between intramolecular bonds and intermolecular bonds, and we'll be able to get some practice and learn more about bonds as we move forward in our course. I'll see you all in our next video.

Introduction to Chemical Bonding Example 1

So here we have an example problem that says the hydrogen fluoride or HF molecules below are interacting with each other through which types of bonds. And we've got these 4 potential answer options down below. And so notice in this image on the left-hand side box in blue, we have one of the hydrogen fluoride molecules, and then on the right-hand side, boxed in blue, we have the other hydrogen fluoride molecule. And so notice that these 2 separate hydrogen fluoride molecules are interacting with each other through this yellow highlighted interaction or this yellow highlighted bond that we can see here. And what you'll notice is that this interaction, this bond that is highlighted in yellow, is not trapped within either of these hydrogen fluoride molecules. It exists between the 2 molecules. And so because that's the case, we know that it must be an intermolecular bond because intermolecular bonds are not trapped within a molecule. They exist between separate molecules. So option C is going to be the correct answer here.

Now option A says intramolecular bond, which we recall from our last lesson video, is trapped within a molecule. And so again, this yellow highlighted bond here is not trapped within either of these two hydrogen fluoride molecules. Instead, this bond that you can see highlighted here in red and this bond over here that you can see highlighted here in red are intramolecular bonds because they are trapped within the hydrogen fluoride molecules, if you will. So, again, we can eliminate answer option A for that reason.

Now option B says extramolecular bond, which is not a type of bond that we've talked about in our previous lesson videos, and this isn't really a thing, so we can cross off option B. And then, of course, we can cross off option D, which says none of the above. So again, C here is the correct answer, and I'll see you all 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 within the molecule. Inter means between the molecules. So this is the bonds between molecules. So intramolecular bonds ìbetween atoms of the same molecule while intermolecular bonds between two different molecules. Okay. So, now we have these different molecules. So this is one molecule, this is one molecule, and this is one 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 form one molecule. Okay? Alright. So now you can tell that we technically have three 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 gonna 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 a dashed line, while intramolecular bonds are generally going to be drawn as a solid line. So you can see that we have three molecules of hydrogen sulfide, and you're gonna 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

In this video, we're going to talk about this image that you see down below, which is actually our map of the lesson on chemical bonding. Notice that the title of this map says "chemical bonds," and everything down below are really just different types of chemical bonds. Since this is a map of our lesson, you can actually use it as a table of contents to figure out what videos are going to be coming up next. The way that this map works is we'll be exploring the leftmost branches first, so we'll start off talking about covalent bonds and then, we'll move on to talk about nonpolar covalent bonds and the equal sharing of electrons between them. After we explore the leftmost branches, we'll zoom out and start to explore the right branches. We'll talk about polar covalent bonds and the equal sharing of electrons. Then, after we finish with covalent bonds, we'll zoom out and talk about non-covalent bonds, including the strong electrostatic interactions like the strong muscle man that you see here in this electrocution symbol, and then we'll move on to talk about different types of strong electrostatic interactions like ionic bonds and hydrogen bonds. One thing that we're not really going to talk much about in our course are actually these weak Van der Waals interactions, which are another type of non-covalent bond, and that's because you'll probably learn more about these weak Van der Waals interactions in a Chemistry course, but for our Biology course, we're going to focus on the green-highlighted portions that you see here. Moving forward in our course, we're going to talk about the covalent bonds next, so I'll see you all in that 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 defined as a substance that contains two or more 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, in a water molecule (H₂O), the bonds between hydrogen and oxygen atoms are intramolecular. Intermolecular bonds, on the other hand, are interactions between atoms of different molecules. For instance, the hydrogen bonds between two water molecules are intermolecular. Understanding these bonds is crucial for grasping chemical interactions and 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 for scientists to communicate and understand the composition of substances.

What are covalent bonds and how do they differ from ionic bonds?

Covalent bonds involve the sharing of electrons between atoms, forming a stable balance of attractive and repulsive forces. For example, in a water molecule (H₂O), the hydrogen and oxygen atoms share electrons. Ionic bonds, on the other hand, involve the transfer of electrons from one atom to another, resulting in the formation of positively and negatively charged ions. For instance, in sodium chloride (NaCl), sodium donates an electron to chlorine, forming Na⁺ and Cl^- ions. Covalent bonds are generally stronger and more stable than ionic bonds.

What are Van der Waals interactions?

Van der Waals interactions are weak, non-covalent forces that occur between molecules. These interactions include attractions and repulsions between atoms, molecules, and surfaces, and are caused by temporary dipoles that occur due to the movement of electrons. Although weak compared to covalent and ionic bonds, Van der Waals interactions play a crucial role in the physical properties of substances, such as boiling and melting points, and are significant in biological processes like protein folding.