In this video, we're going to go over the nomenclature of ionic compounds, particularly those that have polyatomic ions and transition metals. So you need to know the names of certain polyatomic ions. So let's say if you have SO3 2-, this is called sulfite. Let's review some polyatomic ions. SO4 2-.
This is called sulfate. S2-is a monatomic ion. And monatomic ions, they typically end in IDE instead of I or 8. So this is called sulfide. What do you think the names for these ions are? PO4 3-is known as phosphate.
PO3 3-is called phosphite. 8 usually has one more oxygen than 8. And P-3, that's a monoatomic ion, it's phosphide. What about these ClO4-, ClO3-, ClO2-, ClO-, and Cl-? ClO4 is called perchlorate. ClO3.
is chlorate, ClO2-is chlorite, ClO-is hypochlorite, and the monatomic ion Cl-is chloride with an ide suffix. Now there's some other ions that you should know. Feel free to pause the video and write the names of these ions and see if you have the correct answer. OH-is known as hydroxide. CO3 2-is called carbonate.
NO3-is nitrate. NO2-nitrite, which has one less oxygen than 8. And this is called acetate. See if you know these. CrO4 2-is known as chromate.
CR2O7 2-is called a dichromate. MnO4-is permanganate. And Cn-is cyanide.
And C2O2-is oxalate. Now let's go over some examples. Let's say if you want to name the compound NaCl.
How can you do it? So the first atom, Na, you simply need to write the name. Na is known as sodium. Now Cl is chlorine, but instead of saying chlorine, you want to say chloride. For the last part, you need to add the end in ide.
So NaCl is composed of sodium ions and chloride ions. Here we have a monoatomic anion, and Cl-is known as chloride. Now let's say if we want to name KClO3.
The first element, K, is simply called potassium. The second part, the polyatomic ion, you simply just need to know what the name is. ClO3 is called chlorate, so this is potassium chlorate.
Go ahead and write the names of the following compounds. So what's the first one? The first element, Na, is called sodium, and CO3 is the carbonate polyatomic ion.
So this is called sodium carbonate. For the second one, Mg is magnesium. And we simply have S, which is a monatomic ion, so it's going to have the end in IDE, so it's magnesium sulfide. BA is known as barium. And SO2-is a polyatomic ion called sulfate.
So it's barium sulfate. And the last one, Al is aluminum. And the OH part is hydroxide. So combined, it's simply aluminum hydroxide. Well, I'm sure by now you must be saying to yourself, it can't be that easy.
And there are some harder examples, particularly with the transition metals, where you have multiple oxidation states. For example, how would you name... FeCl2 and FeCl3.
Now it turns out that FeCl2 is called iron chloride. And it's not necessarily because there's a 2 here. What it really represents is the oxidation state, or the charge, on Fe. Now, chlorine, as an ion, has a negative 1 charge.
And because of the subscript, there's two chloride ions. So Fe needs to have a charge that balances those two negative charges. The total negative charge is negative 2. And we only have one Fe particle, so it has to have a charge of plus 2 to neutralize the total negative 2 charge by the 2 chloride ions.
So therefore, it's called iron 2 chloride. FeCl3 is known as iron 3 chloride because the charge on iron is plus 3. It has to have a charge of plus 3 to neutralize the 3 chloride ions, which has a net charge of negative 3. And so that's how you can write the name for an ionic compound that has a transition metal with multiple oxidation states. You need to use a Roman numeral to specify the charge of the metal. So let's go over the Roman numeral system. This represents 1. This number is 2. And this number is 3. Now, if you see a V, V represents 5. Now, if you see like an I that's to the left of the V, that means 5 minus 1, which is really 4. Now, if you see an i symbol to the right of the v instead of the left, it's 5 plus 1, which correlates to 6. And if you see this, that's 5 plus 2, which is 7. Now let's go back to Fe.
How would you name Fe s and Fe2s3? Now notice that the coefficient is 1, but it's not Rn1. sulfide it turns out this is called iron sulfide and the reason for that is because the charge on sulfur is negative two and therefore the charge on Fe must be plus two to balance it because they exist in a one-to-one ratio Now, if you seem confused by this, you can write an equation to solve for the oxidation state of Fe.
So it's going to be Fe plus S is equal to 0. The 0 comes from the fact that the net charge of this compound is 0. It's neutral overall. Now, to find the answer to solve for Fe, you need to know the charge on the compound. sulfur so you need to know the common charges of the monatomic ions. Sulfur has a charge of negative 2 when it's the most electronegative element in the compound. So to solve for Fe you need to add 2 to both sides and you can see that that Fe has a charge of plus 2. So now what about the example on the bottom?
What is the oxidation state of Fe in Fe2S3? So let's write an equation. plus 3s is equal to 0. The charge on sulfur, we know it to be negative 2. So 3 times negative 2 is negative 6. And let's add 6 to both sides. So at this point, we can see that 2FE is equal to positive 6. So if we divide both sides by 2, FE has a charge of 6 divided by 2, which is plus 3. So it's in the plus 3 oxidation state.
So now we can write the name of the compound. So we know it's iron 3 sulfide. Since Fe has a plus 3 charge.
Sometimes the oxidation state is going to be this number, sometimes it's not. So don't always rely on it, but it's a possible, it's an indicator that it could be plus 3. Just not all the time. Now let's go over...
the charges of certain monatomic ions. The group 1 metals like sodium, lithium, potassium, even hydrogen which is a nonmetal. The elements in the first column typically form ions with a plus one charge.
The elements in the second column, like calcium, magnesium, strontium, these two or three they form charges that are of the plus two magnitude since they have two valence electrons by the way lithium is above sodium so I really didn't put this in order then in group 3a which is like group 13 on the periodic table you have elements such as aluminum and gallium and these guys they form ions with a plus three charge Now the group 4a elements such as silicon, germanium, tin, lead, typically they form plus 2 and plus 4 oxidation states. And then you have elements like nitrogen and phosphorus. These elements, like most nonmetals, they like to acquire electrons.
So they like to form ions with a negative 3 charge. And then you have the chalcogens like oxygen, sulfur, and selenium. they like to form a minus 2 charge and then the halogens which are very reactive nonmetals like fluorine chlorine bromine and iodine they form negative one charges So knowing that information can help you to determine the oxidation state of a transition metal. So let's try these examples. Name PBO and PBO2.
So, Pb stands for lead. O is oxide, as a monatomic ion. So, we have lead oxide. We just need to know more of the oxidation status for this particular. substance so if we write an equation PB plus oxygen equals a net charge of zero we know that oxygen has a charge of negative 2 so if we add 2 to both sides we can see that PB is in the plus 2 oxidation state therefore to name it it's going to be called lead 2 oxide so now what about the other compound well let's write an equation so we have PB plus two oxygen atoms is equal to zero so let's replace O with negative 2 2 times negative 2 is negative 4 and if we add 4 to both sides PB is in the plus 4 oxidation state so therefore to name it It's going to be called lead oxide.
Let's try this one. Let's see. P3, P5, and...
SN3PO4 4. So feel free to pause the video and try those examples. So V is vanadium, P is phosphorus, but P is going to be the phosphide ion. So we have vanadium phosphide, but we've got to find the oxidation state.
So let's write an equation. 3V plus 5P is equal to 0. Now, phosphorus, as an ion, has a negative 3 charge. It's in group 5A of the periodic table. So, 5 and negative 3 is negative 15. So, if we add 15 to both sides, 3V is equal to plus 15. And then, if we divide by 3, vanadium is in the plus 5 oxidation state. So to name it, it's going to be called vanadium 5-phosphide.
So let's try our last example. Sn is 10-po4-phosphate. So let's calculate the oxidation state.
So we have 3... Now you want to view phosphate as a single unit because you know the overall charge. So we have four phosphate units and the net charge is zero.
So phosphate as a polyatomic ion has a net charge of zero. charge of minus 3 so 4 times negative 3 is negative 12 if we add 12 to both sides we get this and our last step is to divide by 3 so therefore 12 divided by 3 is 4 so 10 is in the plus 4 oxidation state so now we can write the name so it's going to be called 10 4. Phosphate. So now you know how to name ionic compounds that contain transition metals and even polyatomic ions.