Ionic vs. Molecular
In this video we're going to look at compounds that are
ionicversus compounds that are
molecularalso known as covalent. We will learn how you can tell them apart based on their formulas and then we'll look at some important differences between them. So how can you tell whether something is
molecular? Well it depends on the elements that may come up. So
ioniccompounds are made of metals and nonmetals whereas
molecularalso known as covalent compounds are made of only nonmetals. Let's do a couple practice problems to work on this. You will need a periodic table to do this, here's the one that I'm using, I've left out a lot of the elements because they're not important. But what is important is this big thick staircase that divides the periodic table into two parts. On this side of the staircase are the medals and on this side of the staircase are the nonmetals. Okay, so here are a couple examples. The first one, Sulfur Dioxide, so where are the elements that it�s made of. It's made up of Sulfur and oxygen, both these are nonmetals, which means that Sulfur Dioxide (SO2) is a
molecularcompound. Sodium Chloride is made up of Sodium, a metal, and Chlorine or Chloride which is a non-metal. Sodium Chloride is an
ioniccompound. Alright now, H2O is made of Hydrogen and Oxygen. Now you might think that Hydrogen is a metal because it's on this side of the periodic table, it�s fine and understandable if you do that. But Hydrogen is an...
exception, even though it's on this side of the periodic table it�s actually a non-metal, it's the only exception. So Hydrogen and Oxygen are actually both nonmetals which means that H2O water is a
molecularor covalent compound. Okay Copper (II) Fluoride, Copper is here and Fluorine or Fluoride is here, metal, non-metal so this thing is
ionic. Okay, let's look at a few trickier examples. So far, we've only look at compounds that have two elements but there are a lot of compounds out there that have more than two elements, okay? So Propanol for example is made up of Carbon, Hydrogen and Oxygen. All three of these are non-metals though so this is still a
molecularor covalent compound even though it has a bunch of nonmetals, okay? Don't be confused by that. Here's another example. Lithium Nitrate has Lithium which is a metal but then it also has Nitrogen and Oxygen which are both nonmetals. So it still has that metal, nonmetal thing going on so it's an
ioniccompound even though it has two nonmetals and the same thing is true of Sodium Sulfate. It's got Sodium, a metal, and two nonmetals, Sulfur and Oxygen but metal and nonmetal means it�s
ionic. Now Lithium Nitrate and Sodium Sulfate are actually special kinds of
ioniccompounds because they have two different nonmetals in them. They are what are called polyatomic
ioniccompounds and if you want to learn more about these I've got videos on them. So now we can look at a chemical formula...
and we can sort them and we can decide whether something is
ionicor whether it�s
molecularor covalent. So what? Who cares? Well there are some very important differences between
molecularcompounds. Let's take a look at some of those right now. So one really important difference is how the atoms in these compounds are held together. In
molecularor covalent compounds, the atoms that make them up are held together because they're sharing electrons. Here's what I mean. Water, H2O, is a very common
molecularcompound. It's made up of one Oxygen and two Hydrogens and these lines between the atoms show they're connected and they mean that they're connected because they're sharing electrons. Here's how I like to think about this. It's like Oxygen and Hydrogen both have these little hands and the hands are joined together, it�s like their holding hands and they're holding hands because they both are trying to hold on to a pair of electrons which I've drawn here in red. You got Oxygen and Hydrogen connected together because they're holding on and sharing these electrons here, that's what makes atoms connect and stick together in a
molecularor covalent compound, okay? Now on the other hand, in
ioniccompounds, atoms aren�t being so nice to each other�they're not sharing. The atoms stick together in an
ioniccompound because one atom steals another atoms electron, so electrons get stolen, and then...
opposite charges attract. Let me show you what I mean. So Sodium Chloride or NaCl is a very common
ioniccompound, it's made up of Sodium and Chlorine and here they are just hanging out. Now for these two guys to stick together, here is what happens. The first thing that happens is Chlorine reaches its greedy hand over and grabs an electron from Sodium, okay, and it pulls it back. So now, Chlorine has an extra electron and Sodium has lost one of its electrons. This causes Chlorine to now get a negative charge because it has a new electron and Sodium because it had one of its electron stolen now it has a positive charge. So now we have a positively charged ion here and another negatively charged ion here. What do opposite charged things like to do? They like to come together, they stick together, they are attracted to each other just like magnets. So now, we have a positively charged thing and a negatively charged thing. These arrows show how they're going to come together and we end up with the two atoms stuck together because they're oppositely changed and that's what holds
ioniccompounds together. So covalent or
molecularcompounds, the atoms are stuck together because they're sharing electrons with each other.
Ioniccompounds, atoms are stuck together because one has stolen the others electrons, it's given them opposite charges and then those opposite charges have attracted just like magnets. That is one way that
differ. Here is one more. So another big difference is how these compounds would actually look if we could see the atoms that make them up. So
molecularor covalent compounds are made of molecules, which is a fancy word for a bunch of atoms that are stuck together in a clump. Here's what I mean. So sugar is a very common type of a covalent compound and it is made of molecules, where I have these atoms here stuck together in a clump-- two Carbons, four Hydrogens and two Oxygens. So a grain of sugar would look like this, it would look like a number of different sugar molecules that have all kind of come together and formed a clump here, okay? But the big deal here is that these molecules are individual clumps of atoms that then come together to make stuff. On the other hand,
ioniccompounds� they're not made of clumps of atoms like molecules. They�re made of what we call lattice structures and here's what lattice structures are. The example I'm going to give you is salt which is Sodium Chloride table salt and the lattice structures of Sodium Chloride look like this. Look how different this is from the molecules that makeup sugar. You just have the Sodium and the Chloride atoms stuck together in this very organized box-like shape. This is what a lattice structure is. There aren�t individual clumps of Sodium Chloride the way there are individual clumps of sugar, instead all the atoms are stuck together in this very regular shape. Now one big important...
difference between covalent or