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 minus this is called sulfine let's review some polyatomic ions s so42 minus this is called sulfane S2 minus is a monoatomic ion and monoatomic ions they typically end in ide instead of I or8 so this is called sulfide what do you think the names for these ions are p43 minus is known as phosphate p33 minus is called phosphite Eight usually has one more oxygen than I and P minus 3 that's a monoatomic ion it's phosphide what about these cl4 minus cl3 minus cl2 minus CL minus and cl minus cl4 is called per chlorate cl3 is chlorate cl2 minus is chlorite CL minus is hypo chlorite and the monoatomic ion CL minus 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 minus is known as hydroxide CO3 2us is called carbonate NO3 minus is nitrate NO2 minus nitrite which has one less oxygen than eight and this is called acetate see if you know these c42 minus is known as chromate cr207 2 minus is called di chromate M4 minus is permanganate and CN minus is cyanide and c202 minus 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 NAC is composed of sodium ions and chloride ions here we have a monoatomic anion and cl minus is known as chloride now let's say if we want to name kcl3 the first element K is simply called potassium the second part the polyatomic ion you simply just need to know what the name is cl3 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 monoatomic ion so it's going to have the end in ide so it's magnesium suide ba is known as barium and S so42 minus it's a polyatomic ion called sulfate so it's barium sulfate and the last one Al is aluminum and The O 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 fe2 and fe3 now it turns out that Fe cl2 is called iron 2 chloride and it's not necessarily because there's a two here what it really represents is the oxidation state or the charge on Fe now chlorine as an ion has a negative one 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 -2 and we only have one Fe particle so it has to have a charge of plus two to neutralize the total -2 charge um by the two chloride ions so therefore it's called iron 2 chloride F3 is known as iron 3 chloride because the charge on iron is plus three it has to have a charge of plus three to neutralize the three chloride ions which has a net charge of3 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 one this number is two and this number is three now if you see a v v represents five now if you see like an i that's to the left of the V that means 5 minus one which is really four now if you see an I symbol to the right of the V instead of the left it's 5 + 1 which correlates to six and if you see this that's 5 + 2 which is 7 now let's go back to Fe how would you name f s and fe2 S3 now notice that the coefficient is one but it's not rn1 sulfide it turns out this is called rn2 sulfide and the reason for that is because the charge on sulfur is -2 and therefore the charge on Fe must be plus two to balance it because they exist in the 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 f is equal to Z the zero comes from the fact that the net charge of this compound is zero it's neutral overall now to find the answer to solve for Fe you need to know the charge on sulfur so you need to know the common charges of the monoatomic ions sulfur has a charge of -2 when it's the most electronegative element in the compound so to solve for Fe you need to add two to both sides and you can see that Fe has a charge of plus two so now what about the example on the bottom what is the oxidation state of Fe in fe2 S3 so let's write an equation 2 Fe + 3 S is equal to 0 the charge on sulfur we know it to be -2 so 3 * -2 is -6 and let's add six to both sides so at this point you can see that 2 Fe is equal to POS 6 so if we divide both sides by two Fe has a charge of 6 / 2 which is+ three so it's in the plus three 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 three 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 three just not all the time now let's go over the charges of certain monoatomic ions the group one metals like sodium lithium potassium even hydrogen which is a non-metal the elements in the First Column typically form ions with a plus one charge the elements in the second column like uh 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 put this in order then in group 3A which is like Group 13 on the prag table you have elements such as aluminum gallium and these guys they form ions with a plus three charge now the group 4 a elements such as uh silicon germanium tin lead typically they form plus two and plus4 oxidation States and then you have elements like nitrogen and phosphorus these elements like most non-metals they like to acquire electrons so they like to form ions with a neg3 charge and then you have the cogens like oxygen sulfur and selenium they like to form a minus two charge and then the halogens which are very reactive nonmetals like Florine 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 monoatomic ion so we have lead oxide we just need to know what 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 -2 so if we add two to both sides we can see that PB is in the plus two oxidation state therefore to name it it's going to be called lead to oxide so now what about the other compound well let's write an equation so we have PB plus 2 oxygen atoms is equal to Z so let's replace o with -2 2 * -2 is4 and if we add four to both sides PB is in the plus4 oxidation state so therefore to name it it's going to be called lead for oxide try this one let's see V3 P5 and SN 3 p44 so feel free to pause the video and try those examples so V is vadium p is phosphorus but p is going to be the phosphide ion so we have vadium phosphide but we got to find the oxidation state so let's write an equation 3v + 5 p is equal to0 now phosphorus as an ion has a neg3 charge it's in group 5 a of the periodic table so 5 and3 is5 so if we add 15 to both sides 3v is equal to+ 15 and then if we divide by three vadium is in a plus five oxidation state so to name it it's going to be called vadium five phosphide so let's try our last example SN is 10 P4 is phosphate so let's calculate the oxidation state so we have 3 SN now you want to view fos phate 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 minus three so 4 * -3 is -12 if we add 12 to both sides we get this and our last step is to divide by three so therefore 12 / 3 3 is4 so 10 is in the plus4 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