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Naming Covalent Molecular Compounds

Naming Covalent Molecular Compounds
let's look at how to write names for

compounds

like these that are made of two nonmetals the nonmetals are the elements to the right of the staircase on the periodic table now

compounds

like these that are made of a nonmetal and another nonmetal two nonmetals are called

covalent

or

molecular

compounds

and that's because the elements that are in them are held together by

covalent

bonds and they're held together in groups called molecules now the way we name

covalent

or

molecular

naming covalent molecular compounds

compounds

is different from how we name ionic

compounds

ionic

compounds

contain a metal and a nonmetal 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 ii 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 nonmetal it's an ionic
compound I have a whole bunch of videos on how to name I on a

compounds

and how to write formulas for them if you need to name a compound that's made of a nonmetal and another nonmetal well that's a

covalent

or

molecular

compound and

naming

these is what this video is going to focus on okay here's our first chemical formula n 2o 3 it's made of two nonmetals 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 IDE name now the IDE name is the version of the element name that ends in IDE these are actually
the same names that we 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 we put on the front of each name to tell us how many atoms of each type we have so n 2 we got two nitrogens which means that we want to use this prefix for to die so put that in front of the
element name dinitrogen now o 3 which means that we have three oxygens so i'm going to use the prefix tri here and write that in front of oxide and so the name for this compound is dinitrogen trioxide we put the element name here we put the IBE name here and then we use the prefixes to indicate how many atoms of each type we have let's look at a few more examples P for s 10 okay for the first element we'll start with the element name P is phosphors if you didn't know that you
naming covalent molecular compounds
could look it up on the periodic table for the second element that's s here start with a IDE name so s is sulfur and it's 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 P four so that means we have four phosphorus atoms so four is tetra we use the tetra prefix tetra and then four sulfide we got ten so we'll use this prefix deca deca so the name of this compound is tetra phosphorus deca sulfide
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 that's carbon and then the second element which is fluorine we use the IE de name which in this case is fluoride okay now we get to
the prefixed 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 fluorine here
in front of fluoride I'll put the prefix just like I would any other time so I have four of these fluorines so i'm going to call it tetra tetrafluoride so carbon tetrafluoride not mono carbon tetrafluoride just carbon tetrafluoride 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 chlorines 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 ten two here as the prefix so it's going to be Penta Penta chloride and phosphorus pentachloride not mono phosphorus pentachloride just phosphorus pentachloride 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
naming covalent molecular compounds
more step to keep in mind and I'm going to show it to you as I work through this example okay CL 2 o so the first element here CL is chlorine and oh 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 dye 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 dichlorine heptoxide hear that hep
dioxide thing is 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 a o or o o turn it into oh here's that means we got this heptoxide here so to make this easier to pronounce we turn the a o 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 name into chlorine heptoxide so not heptoxide but just heptoxide so
you get rid of that a if it's next to an O there let's do one more P 406 so the P phosphorus is our first element and then oh we got oxide that is a 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 hex oxide we get an AO
so we're going to get rid of this a-here soup I always like knock that name out of the way hexa oxide and that turns it into tetra phosphorus hex oxide you know I forgot to circle the name and the last one and this is just so satisfying so I did it really slowly to make up for the fact I didn't circle the last one so we get rid of this we get rid of this a-here tetra phosphorus hex oxide so I wanted to 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 O so the first element is carbon the second element is oxygen its ite name is oxide ok 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 oh and if you have one of the second element you do use a prefix so we use the mono prefix here so mono now mono oxide 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 mono oxide 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 pronounciation 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 dire try because they don't end in aro and then for all of these others 4 through 10 we get rid of all of these A's so we get tetroxide pentoxide hex oxide heptoxide oxide non oxide and Dec oxide so here's how we name

covalent

or

molecular

compounds

with two nonmetals 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 a o or o Oh turn it into o keep these things in mind you should be all set