 So, atoms form molecules. We already know a single atom has a nucleus, but somehow multiple atoms connect to each other like Legos and form molecules. So anytime, any number of atoms that we connect together, we connect them with chemical bonds and form all sorts of cool, amazing structures. And all those chemical bonds are those atoms sharing their electrons. Chemical bonds happen because electrons are shared, it's the only way I can think of it. Electrons are shared between nuclei of atoms. Take a look at even when we were talking about the neutrons and the isotopes, I showed you this picture of a glucose molecule and I sort of just glossed right over this thing, but this is actually a molecule. And it's weird the way it's drawn because I can't draw on this one, but oops, go back. You can see at each little, I don't know what that is, angle. At each angle, that is actually representing a carbon atom. And in organic molecules, carbon is the backbone of almost everything that is living. And so they're like, dude, we're not going to write all the C's to show you all the carbons. We're just going to tell you that carbons exist at all the angles. That's cool. This glucose molecule has a certain number, six carbon atoms. You can see that the labeled carbon or labeled glucose also has the same number of carbon atoms and then we layer on oxygen atoms and hydrogen atoms and we put them together in a certain way and now we have a glucose molecule, yum yum. All the atoms are connected by shared electrons. We have, this picture here shows you a hydrogen gas, not that one. Go back, not that one. This one. Slow down, silly. Don't worry, we'll get to that other one. I can't wait to get to that guy. You can see that the electrons, I like this image because it shows you the electrons as sort of a cloud and that's a little more accurate than that sort of vision of orbits almost that the electrons follow. They actually are like most likely to be found in a certain space and I think of them as like a swarm of electrons, like kind of like bees or like this cloud. And you can see that when we have two hydrogen atoms that are connected by a chemical bond, they're actually sharing electrons in that overlapping space. Let's look at, there's two kinds of chemical bonds and I'm gonna write that down for you but that means I have to do this, okay I got there. The two kinds of chemical bonds that we will deal with and there's a flavor of one but we're gonna have covalent bonds and covalent bonds share electrons equally. So when that picture that I had of the two hydrogen atoms forming a chemical bond, they actually form a perfectly covalent bond and they share the electrons equally. So the electron is most likely to be next to hydrogen one as it is next to hydrogen two. In I'm gonna just go ahead and contrast that with an ionic bond. I think of an ionic bond as one atom steals the electrons from the other. And this is just my brain going, okay they're still sharing the electrons because the stolen electrons, if I steal electrons from another atom, that atom I became negatively charged because I just gained an electron. That other atom just lost an electron, it has one less electron which means it now has a positive charge. Does that work for you? And now this negatively charged electron stealer and this positively charged electron wisher that it had an electron or they're gonna stick together because opposite charges attract each other. So they're gonna form a chemical bond because they are now oppositely charged. So the stealing of the electrons creates the bond itself because it creates an electrical difference between the two atoms involved. I'm just gonna give you an example, sodium chloride or table salt is a substance that forms an ionic bond. That's good enough for us. If you throw, well we'll talk about water later, but you can imagine that maybe some molecules, water is one of them, some molecules hog the electrons a little bit more than others and you can end up with a molecule that has, that it's polar and a polar molecule has a covalent bond. There's sharing electrons, the two atoms are sharing electrons, but one atom gets the electrons a little bit more than the other ones. So it ends up with a little bit of a slightly negative charge whereas the other atoms get a slightly positive charge creating a polar molecule, not a completely charged molecule like that happens in the ionic bond, but a slightly charged molecule. And in the next lecture, not today but the next time we hang out and bond in videos, we'll talk about polar molecules because we'll talk about water and water is a very important molecule to life and a lot of its qualities are because it is a polar molecule. Okay, you can imagine that we have sort of a spectrum that between a covalent bond and ionic bond at the ends of our spectrum in between there, we can have this polar covalent bond and really really polar covalent bond or like mildly polar covalent bond and that will impact the way a molecule behaves. Okay, I think that's everything I want you to know about chemical bonds. Super important. Next thing we're going to talk about are chemical reactions, which happen because we break and form chemical bonds.