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 are specific molecules containing at least two different elements. For example, water (H₂O) is both a molecule and a compound, whereas oxygen gas (O₂) is only a molecule. Chemical bonds can be categorized as intramolecular (within a molecule) or intermolecular (between different molecules), with covalent bonds being a primary focus in understanding these interactions.

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 2, 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 the same element or if they're 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 different 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 has 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 type of atoms that are in a molecule or compound. And so an example of a chemical formula is this chemical formula that you see right here, which is the chemical formula for glucose. And so you can see that if scientists had to write out 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 much faster.

So writing down C6H12O6 is much faster than drawing out this entire structure, so chemical formulas can be very 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 h twelve 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. Here, number 1 focuses on intramolecular bonds which are interactions between atoms within the same molecule. The number one mentioned above in the text corresponds with the number 1 on the left-hand side of the image for intramolecular bonds. Let's examine the image down below on the left-hand side.

Notice that in the middle we're showing you a water molecule, H₂O, two hydrogens, one oxygen atom. The lines you see here, forming between these different atoms, represent chemical bonds, which we will discuss more as we move forward. These lines, or chemical bonds, are forming within the same water molecule and are almost 'trapped' within the same molecule. You can remember 'intra' from 'trapped,' indicating that they are confined within the same molecule.

Now, intermolecular bonds are interactions between atoms of different molecules. The number 2 mentioned above corresponds with the number 2 in the image below on the right-hand side. Observe here, where we show two water molecules. Each molecule, one here and another over there, focuses on a bond forming between these two different molecules. As it is forming between two different molecules, it's not 'trapped' within the same molecule, so intermolecular bonds are not trapped.

Think of 'ter' as unable to spell 'trapped,' indicating it's not confined but instead forms between different molecules. It's like one molecule is giving a high five to another molecule, representing the interaction between different molecules. Here, 'inter' is used 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 will be able to practice 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 within the molecule. Inter means between the molecules. So this is the bonds between molecules. So intramolecular bonds are between atoms of the same molecule; intermolecular bonds are 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 single sulfur is 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 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 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 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 a 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 nonpolar covalent bonds. After we've explored the leftmost branches, then we'll start to zoom out and explore the 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 two 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.

Here’s what students ask on this topic:

What is the difference between a molecule and a compound?

A molecule is a group of two or more atoms chemically bound together, 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 consists of hydrogen and oxygen atoms. Therefore, while all compounds are molecules, not all molecules are compounds.

What are intramolecular and intermolecular bonds?

Intramolecular bonds are the forces that hold atoms together within a single molecule. For example, the covalent bonds between hydrogen and oxygen atoms in a water molecule (H₂O) are intramolecular bonds. Intermolecular bonds, on the other hand, are forces that occur between 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 is a notation that uses chemical symbols and numbers to represent the composition of a molecule or compound. For example, the chemical formula for glucose is C₆H₁₂O₆, indicating it contains six carbon atoms, twelve hydrogen atoms, and six 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 are chemical bonds formed by the sharing of electron pairs between atoms. These bonds typically occur between nonmetal atoms. For example, in a water molecule (H₂O), the hydrogen and oxygen atoms share electrons to form covalent bonds. Ionic bonds, on the other hand, are formed by the transfer of electrons from one atom to another, resulting in the formation of positively and negatively charged ions. These bonds usually occur between metal and nonmetal atoms, such as in sodium chloride (NaCl). Covalent bonds involve electron sharing, while ionic bonds involve electron transfer.

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 electron pairs 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 (electron transfer between atoms) and hydrogen bonds (attraction between a hydrogen atom and an electronegative atom). Additionally, weak Van der Waals interactions are another type of noncovalent bond, though they are less emphasized in biology courses.