hi it's mr. Andersen and today I'm going to show you how to name chemical compounds and the reason we do that is when you're done you should be able to pick up anything and figure out what's actually in it so if we've got a can of Mountain Dew this is old-school Mountain Dew and we look at what's inside it there's going to be water and sugar and we know what those things are but there's also going to be for example sodium benzoate and at the end you'll actually know what that is or calcium disodium you should be able to figure that out when we're done what that actually is and so let's get started first of all let's start with the rule of thumb the rule of thumb says that if you hold your thumb up to the periodic table things on one side of your thumb are going to be nonmetals and so if I hold it up like this everything on this side of my thumb is going to be a nonmetal everything on this side of my thumb is going to be a metal and so there are really just three types of bonds if you have two metals together we call that metallic bond if you have two nonmetals together we call that a covalent bond and then if you have one metal and one nonmetal together we call that an ionic bond and if you don't know how to figure out what kind of a bond it is you'll want to look back to the previous podcast where I talked about what exactly that is one quick way to do it is to just look at the differences in the electronegativities so calcium is one if we look over here at for example nitrogen that's three point zero four so I should be able to tell right away that that's going to be an ionic bond just from the electronegativities okay let's start with the easiest one and that is naming covalent compounds first of all you have to figure out how do I know which of the two atoms comes first in other words why is it carbon dioxide and not dioxygen mono carbon carbide excuse me and so let's look on the periodic table and I'll talk about rule one and rule two rule one says you always start with the lower group number and so why is it h2o it's because hydrogen has a lower group number than oxygen which is over here and so hydrogen gets to go first now you might immediately if your smart thing thinking well okay that works we're always going to go kind of from left to right but what if they're in the same column and so sulphur dioxide is an example of that we've got sulfur here and we've got oxygen right above it so who goes first well you're always going to start with the one that has a greater period number and remember period numbers are going to increase as we go down the periodic table and so sulfur goes before oxygen this just because it's lower on the periodic table so once we figure it out who goes first then it's really easy to figure out the names of these so let's start with carbon dioxide carbon dioxide is a carbon is going to go first whenever you're naming covalent compounds you're just going to put the name of the atom first and then you're going to put the anion second on these little subscripts tell you how many of those ions you actually have one more thing so first of all we put the the atom first and then we put the second as a as an ion or this in this case it's a negative ion called an anion and then we're just going to use this chart over here to figure out how many of them we have on it goes from mono meaning one all the way up to deca meaning ten we rarely use these ones down here but you're you might as well learn these first four because we use those quite a bit so let's start with carbon dioxide now you might want to say well there's only one carbon and so let's call that mono carbon but you can see here that you don't put a mono on the first one also if we have like mono oxide that sounds kind of silly you just kind of lump that together and then be monoxide so let's start with the first one so we've got carbon first so we're just going to write the name of that element so carbons first and then we have two of the oxygens and so that's going to be dye oxide and you've heard that before carbon dioxide let's look at the next one then what's the first element elements going to be P is going to be phosphorus and then we have n next now it's not nitrogen it's going to be the ion of nitrogen so let's kind of skip forward and see what that is it's way up here let me get in a color you can see it's going to be nitride and so if you're ever trying to figure out what the ions are you can look on our we use this in class periodic table of ions and it's going to tell you what the that is so let's go back and finish this one out so this one we have phosphorus but we have three of those and so this one is going to be dry phosphorus and then we've got four of these nitrides and so that's going to be tetra nitride so that's the name of P three and four if we go to the next one this is carbon so we're going to just write the name first carbon and then we've got four of these hydrides and so that's going to be carbon tetra hydride so it looks if you look at this again where I was writing the atom number four the atom name first and then we're always going to write this instead of tetra hydrogen is going to be hydride we're going to write that anion for that so that's naming covalent compounds let me erase that and let's go to ionic compounds ionic compounds that it's actually easier there's just two rules rule number one you're always going to write the cation first in the anion second so you're always going to write the positive charge first and the negative charge second and the only other tweak on that is that there are some elements let's kind of skip back for a second so if you look way over here let's look at for example iron iron you can write iron in a number of different ways we can have iron three we can have iron two some of these will have multiple states that they can have and so if there ever could be more than one type like iron three or iron two in Roman numerals we're going to note which one of those are which one they are and so let's take a look at one of these and actually actually do that so let's look at the first one so this is lithium and oxygen and so all we do is look on our chart and we figure out what the name of those ions are so if we go back here here's lithium all the way over here so lithium is going to be the name of the cation and then we go over here and we find the anion and it's just simply lithium oxide and so this one would be lithium oxide now if you look at it why is it written as Li - oh because lithium has a positive charge and oxygen or the oxide anion is going to have a two minus charge so we have to have two of the positive charges to balance that out now let's look at the next one this one looks a little bit scary this one it should you shouldn't be scared though if we ever see something that is written in parentheses that means it's a polyatomic ion that means it's anion still has a charge but it's made up of more than one atom in this case we have NH 4 so let's just go back to our chart and find out where that is now I'm going to look around here until I find it so it's way over here so this is B NH 4 and that stands for ammonia and so that's going to be ammonia and now let's look back at what we had now we have a P and so that's the other part that's going to be our hand so let's find that that's going to be phosphide over here so if we look at ammonia there's only one type it can be nh4+ and phosphide is going to be P and so let's just kind of go forward and write that is so that is mo neum phosphide so again pretty easy we're just writing the cation first and then the anion second now let's look at this one we've got copper and then it looks like we have another one of those polyatomic ions this case it's going to be an anion so let's go find it on the chart first of all we have to find copper and so copper I've kind of written all over it but copper is going to be where's copper going to be copper is going to be right here and so copper can have two states carpet can either be Cu 2 plus or it could also be Cu 1 plus or just plus and so we have to figure out which one it's going to be so let's go take a look at that so here we've got copper and now we've got this we got to figure out what that no.3 is so let's go back again so where is no.3 no.3 is going to be written on our chart looks like I'm going to have to erase some of this stuff so if we look up here no.3 on our chart is going to be night no.3 is going to be nitrate and so nitrate is going to be right here its no.3 and it has a 1 minus charge and so now we've got our copper which we know could be copper - or copper one and now we know that Nate rate has a minus one charge let's try and figure out what this is so nitrate has a minus one charge so this is minus one for this nitrate right here but we don't just have one of them we actually have two of those that's what the subscript means down here and so on the right side of this we have two of these minus one charges and so we have a two minus charge on the right side if you look on the left side well what copper do we have well we know right away that since there's two minus charge on this side we actually have copper - so let's that write that out it's going to be copper now we know it's going to be copper - so in Roman numerals in there I'm going to put copper - and that's going to be nitrate so again the only time we have to write those Roman numerals is if it could exist in two different states let's go to the next one looks like we've got nickel here and then we've got so3 so figure out what so3 is let's go back so let's find so3 on here so3 is actually going to be sulfite and it has a two minus charge now if we find nickel nickel can either be nickel two or it can be nickel three so again we've got sulfite and we've got nickel and you got to kind of switch between these so now we've got nickel and we got sulfite sulfite remember had sulfite had a let me go check again had a two minus charge and so this has a two minus charge on this side and we have three of those and so what do we have on the net right side we actually have a six minus charge on the right side and so what nickel do we have well if we look on the left side we have two of these and so to balance out that six minus charge on the right it has to be nickel three and then on the right side that's going to be sulfite we had some dots here and so we know that it's balanced on either side so we're going to call that nickel three sulfite