Naming Ionic and Molecular Compounds | How to Pass Chemistry

In this video you will learn the different types of combinations to name

ionic

and

molecular

compounds

, also known as covalent

compounds

. Alright, let's do this! Hello Hello Melissa Maribel and I help students like you understand what they just learned in class. This way you stress less and graduate faster. Alright guys, this is a very VERY important lesson today, because you will be

naming

compounds until the end of the semester and if you decide to continue with

chemistry

, you will be

naming

compounds forever. So if you need to pause playback or type something, do so. I'll let you know what you need to understand versus what you need to memorize.

Well, here is a simple strategy that has helped my students remember how to name compounds correctly. The strategy is to identify the type of compound from the beginning. Whether

ionic

or

molecular

. Molecular refers to covalent compounds. An ionic compound consists of a metal and a nonmetal. A covalent compound consists of two nonmetals. When looking at the periodic table, the highlighted part shows the different types of nonmetals. Everything after that is metal. We will start with the different types of naming of ionic compounds. The first, ionic compounds without transition metal. Aluminum Oxide shows you the name of the metal, our aluminum and oxygen, or our nonmetal, which ends in "ide." Looking at the periodic table we need to identify our charges, so if you have to pause the video and write them down, these are the charges you should have memorized.

For ionic compounds you will always have to balance your charges. For this aluminum oxide example, let's identify the charges on aluminum and oxygen. The charge on aluminum is a 3+ charge and oxygen has a 2- charge. The aluminum had that 3+ charge and the oxygen had the 2- charge. Let's balance these charges by multiplying our aluminum or actually putting a subscript of 2, that 2 is then multiplied with our 3+ charge and becomes a 6+ charge. We want these charges to be exactly the same. Then I'll also put in a subscript 3, which would then turn this 2 load into 6 and our loads will be balanced.

Another way to look at this is actually "lasing," I've heard that term before, our charges where our aluminum gets that 2 and the oxygen then gets the 3. They get the charges opposite each other just so they can make the exact same charge. Then they would drop the charges and be neutral. And our final balanced compound is aluminum oxide which has the subscript 2 and 3. The second one is ionic compounds with a transition metal. It consists of the name of our transition metal, a Roman numeral in parentheses, and a nonmetal ending in "ide." Our transition metal is iron and our Roman numeral is 3.

Your Roman numeral actually tells you the charge of your transition metal. Many times transition metals have different types of charges. Iron sometimes has a 2+ or 3+ charge, so our Roman numeral actually tells us the charge of what iron is, within this compound. Its nonmetal is oxygen and once again ends in "ide." That's why we need to balance our loads. His iron, as we saw, had a charge of 3+, his oxygen had a charge of 2-. To balance these charges, we will place a subscript 2 for our iron and a subscript 3 for oxygen. Now we have these six canceling out, which is what we wanted, and the final compound is Fe2O3.

Polyatomic atoms simply means that there are two or more elements within that atom. Get to know these polyatomic atoms. Write some flashcards. I will also put a link in the description box to more polyatomic atoms that you should also know about. Moving on to ionic compounds with a polyatomic atom. They consist of the name of our metal and our polyatomic atom. Note that it does not have its non-metallic ending in "ide". Many times polyatomic atoms end in "ate" or "ite", except for hydroxide and cyanide. We have calcium phosphate. Calcium is the name of our metal and phosphate is our type of polyatomic atom.

Polyatomic atoms have specific charges, so again, this is something you should know. Calcium has a 2+ charge, phosphate has a 3- charge. Our phosphate started with four oxygens. So to balance our charges, we need to put this in parentheses to isolate that phosphate group. By doing so we will place our three with our calcium, that will again give us a charge of 6+. We'll place our 2 outside the parentheses. Polyatomic atoms tend to have parentheses whenever we place a subscript. These are now balanced and their final compound is calcium phosphate. This way it is correctly balanced. Our latest ionic compound mixes transition metals and polyatomic atoms.

It consists of the name of the transition metal, a Roman numeral, and the polyatomic atom. Here we will see Copper (II), once again (II) tells us the charge of copper, which is our transition metal, and our polyatomic nitrate atom. Nitrate is NO3 and has a -1 charge. We saw that copper had that 2+ charge, so all we have to do is simply have a 2 for our nitrate, since copper is already 2. To balance our charges, we'll put this in parentheses and put our subscript 2 outside and make these two cancel each other out. Its final compound is copper nitrate with a subscript 2 only in the nitrate.

Let's start backing up now. So instead of having the name of the compound, they give us the formula and ask us to write the name of the compound. FeBr2, Fe is known as iron and Br is known as bromine. Iron is a type of transition metal, bromine is a nonmetal. So our nonmetal will end in "ide" and we know that a transition metal will have a Roman numeral. To find out what your Roman numeral is, let's go back to the general positions. So bromine is a type of halogen, meaning it has a charge of -1. So since this had a charge of -1, Fe or Iron, it must have had a charge of 2+.

Another way to identify this is that if we went back, this 2 would return to iron, since bromine needed 2 to fully balance the charges. Then we will have iron (II) bromide. Let's try another example like that. Cu3(PO4)2. Cu is known as copper. It is a type of transition metal so we have to have a Roman numeral. PO4 is a type of polyatomic atom. We had to know that the charge of polyatomic atoms was 3- because this allows us to discover that copper had a 2+ charge. Another way to look at this is that this 2 goes back to the previous element.

So that 2 belongs to copper and this 3 belongs to our phosphate group. That's a trick you can use as long as you use your formula and try to get back to the actual name of the compound. So the name of our compound would be copper(II) phosphate. Those are all different types of combinations of ionic compounds. Moving on to covalent or molecular compounds. Something we have to know are the prefixes. Know from 1 to 10 because it is not necessary to balance any of the charges, I repeat for covalent compounds do not balance the charges. Covalent compounds consist of two non-metals as we mentioned before.

The setup will be that there is one prefix plus the name of your nonmetal, then another prefix plus the name of your nonmetal that ends in "ide." Diphosphorus Pentoxide. You'll also hear this as pentaoxide. The most common form is pentoxide. Our subscript is "Di" and "Pent". "Di" means two and "Pent" ​​means five. Again, we don't have to balance any charges. All you have to notice is that "Di" means two, so there are two matches. The "Pent" ​​means five, so there are five oxygen. That's it, you're not done without balance charges. Your prefixes literally tell you how much of that element there is.

We have N3O6. We will look at the different subscripts and find out which prefix they need. So our three means "tri" and six means "hexa." So we'll put in "tri" and then the name of our nonmetal which was nitrogen, then we'll put in "hexa" and the name of our other nonmetal that ends in "ide." So we have trinitrogen hexaoxide. Now I hope you don't plan to leave here without practicing what you just learned. (Music) If you need more help, I will do online tutoring from time to time, so sign up. I'll put a link in the description box.

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