let's look at how to write names for compounds like these that are made of two non-metals the non-metals are the elements to the right of the staircase on the periodic table now compounds like these that are made of a non-metal and another non-metal two non-metals are called Cove valent or molecular compounds and that's because the elements that are in them are held together by calent bonds and they're held together in groups called molecules now the way we name Cove valent or molecular compounds is different from how we name ionic compounds ionic compounds contain a metal and a non-metal the metals are the elements here on the periodic table and I've written in some of the most common some examples of ionic compounds and of how we name them are things like calcium fluoride and iron 2 oxide so if you have to name a compound the first thing you want to do is figure out what type of elements are in it if the compound is made of a metal and a non-metal it's an ionic compound I have a whole bunch of videos on how to name ionic compounds and how to write formulas for them if you need to name a compound that's made of a non-metal and another non-metal well that's a calent or molecular compound and naming these is what this video is going to focus on okay here's our first chemical formula n23 it's made of two non-metals we're going to write a name for it following these steps so here's the first one says for the first element start with the element name what I'm talking about the first element I'm talking about the order that these elements are in in this chemical formula so the first element here is nitrogen n so it says start with the element name okay so I'm going to put nitrogen down that's the element name here now for the second element so that's this here oxygen for the second element start with the ID name now the IDE name is the version of the element name that ends in ide these are actually the same names that we'd use to name negative ions so we've got oxygen here we're going to use its IDE name which is oxide okay so we got nitrogen and we got oxide now use prefixes to show how many atoms of each type there are the prefixes here's a list of them are like these little tags that put on the front of each name to tell us how many atoms of each type we have so N2 we got two nitrogens which means we want to use this prefix for two D so put that in front of the element name d nitrogen now o03 which means that we have three oxygens so I'm going to use the prefix try here and write that in front of oxide and so the name for this compound is D nitrogen trioxide we put the element name here we put the IDE name here and then we use the prefixes to indicate how many atoms of each type we had let's look at a few more examples P4 S10 okay for the first element we'll start with the element name p is phosphorus if you didn't know that you could look it up on the periodic table for the second element that's s here start with an IDE name so s is sulfur and its IDE name is sulfide okay so those are the two names now we're going to use prefixes to show how many atoms of each type we have we got P4 so that means we have four phosphorus atoms so four is Tetra we use the Tetra prefix Tetra and then for sulfide we got 10 so we'll use this prefix Deca Deca so the name of this compound is Tetra phosphorus decasulfide let's move on we're going to add a couple more steps to deal with more complex formulas here's the next step that we're going to talk about do not use mono on the first element I'm going to show you what this means by working through naming this formula we'll start it off just normally so for the first element start with the element name name that's carbon and then the second element which is Florine we use the IDE name which in this case is fluoride okay now we get to the prefix part and this is where things change a little bit so it says do not use mono on the first element carbon here we only have one of them so you might want to use mono and put it in front of here that would be a perfectly logical thing to do but for whatever reason we don't use mono on the first element if there's just one of them we just leave it like this you don't put anything there so we have one carbon we're just going to call it carbon and then for Florine here in front of fluoride I'll put the prefix just like I would any other time so I have four of these flines so I'm going to call it Tetra tetrafluoride so carbon tetrafluoride not monocarbon tetrafluoride just carbon Tetra floride is how we name this because if you got just one of the first element you don't use anything pcl5 let's name this so P the first element is phosphorus CL the second element is chlorine and chlorine IDE name is chloride so there it is now we get to the prefixes phosphorus here we only have one of them so we're not going to use mono here we're just going to keep it as phosphorus and chlorine we have five of those so we're going to use Penta here as the the prefix so it's going to be Penta pentac chloride and phosphorus pentac chloride not monop phosphorus pentac chloride just phosphorus pentac chloride is how we name this now there's one more step that we're going to add I'm going to talk about that next okay there's one more step to keep in mind and I'm going to show it to you as I work through this example okay cl207 the first element here CL is chlorine and uh o here is oxygen its IDE name is oxide okay so now the next thing I'm going to do is I'm going to use these prefixes so I got two chlorines so I'm going to use dye DY for two up here and then oxide I got seven of those so I'm going to use the prefix hepta now try saying this compound name we got dorine hepto oxide hear that hepto oxide thing it's kind of awkward to pronounce so to prevent us coming up with these really weird names there's one more Rule and that's that if you have AO or oo turn it into o here's what that means we got this heptoxide here so to make this easier to pronounce we turn the AO that we see right there into just an O so I'm going to get rid of that a going to get rid of that a and I'm going to turn this compound compound name into chlorine heptoxide so not hepto oxide but just heptoxide so you get rid of that a if it's next to an O there let's do one more p406 so the P phosphorus is our first element and then o we got oxide that is ID name for oxygen here all right now let's use the prefixes switch to our prefix table here we have four phosphorus so we're going to use the Tetra prefix so Tetra Tetra phosphorus and then for oxygen we have six of those so we're going to use hexa here and just as before we end up with this awkward name hexoxide we get an AO so we're going to get rid of this a here sh oh I always like knock that name out of the way hexa oxide and that turns it into tetraphosphorus hexoxide you know I forgot to circle the name in the last one and this is just so satisfying so I did it really slowly to make up for the fact I I didn't Circle the last one so we get rid of this we get rid of this a here tetraphosphorus hexoxide so I want to do one more example that pulls in examples of all of this it's like a good review for all of these things here's our last formula this is a really good review it's just C so the first element is carbon the second element is oxygen its IDE name is oxide okay so now for the prefixes carbon we've only got one of them so remember don't put anything in front of it we just call it carbon but we have one o and if you have one of the second element you do use a prefix so we use the mono prefix here so mono now monooxide gives us the same kind of weird pronunciation thing it gives us an oo here so we're going to get rid of this oh I'm going to try to not knock this name out here oh just a little bit really good and we call this we change the name from monooxide to carbon monoxide which is probably something that you've heard of before here's just some quick information about how we change these prefixes to avoid an awkward pronunciation problem we only really have this problem with oxide because it begins in O and so we get rid of the O here in mono and we get monoxide then we don't have to worry about D or try because they don't end in a or o and then for all of these others 4 through 10 we get rid of all of these A's so we get tetroxide pentoxide hexoxide heptoxide octoxide nonoxide and DEC oxide so here's how we name calent or molecular compounds with two non-metals just follow each of these steps one thing to keep in mind this mono for the first element really confuses a lot of people so remember not to use mono if there's just one of the first element keep this in mind try to prevent yourself from writing names that have really awkward pronunciations with AO or oo turn it into o keep these things in mind you should be all set