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Naming Ionic Compounds with Transition Metals Practice Problems

Naming Ionic Compounds with Transition Metals Practice Problems
in this video we're gonna do five

practice

problems

we'll take the chemical formulas for

compounds

that contain

transition

metals

and we'll write names for them now the

transition

metals

are the elements in this part of the periodic table here and I've written in some of the most common I'm also going to be talking about some of the

metals

over here which are not technically

transition

metals

but act a lot like the

transition

metals

in certain ways now when we write the names
naming ionic compounds with transition metals practice problems
for formulas that contain

transition

metals

those names often have Roman numerals in them and we got to figure out what Roman numeral two put there so we'll get really good at that here now if you need a little background before you get started with this video I'd recommend you check out my video

naming

ionic

compounds

with the

transition

metals

introduction and also have a look at my videos on writing

ionic

formulas if you're all good with that background let's get started
here's our first example see our BR 2 so CR here is chromium it's a

transition

metal and like many

transition

metals

chromium can make a variety of ions with different charges chromium can make three ions it can make CR 2 + CR 3 + + CR 6 + so when we name this compound we have to figure out what charge chromium has here it could be 2 + 3 + or 6 + here's how we figure it out the first thing we're gonna do is we focus in on the ion with a definite charge the island can only have
one charge it doesn't change and here that's br br is in this column this one - column which means that in an

ionic

compound BR always has a charge of 1 - now how much total negative charge do we have here well there's this - after B R which means that we have to be ours in this compound so let me write another one in and each one of these BRS has a charge of 1 - so that means that the total negative charge here is 2 - okay that's negative charge what about positive charge well
in an

ionic

compound you always have to have the positive and a negative charge balanced out so that means that if we have 2 - here we have to have 2 + over here because they balanced now now we can figure out the charge on chromium we have one chromium in here there's no number after this which means that we just have one chromium is our positive ion and we have 2 + of positive charge so that means that this one chromium ion has to hold all of this positive charge because we only have one
of them so that means the charge on chromium is 2 + so we have 1 chromium 2 plus which gives us 2 + of charge which is balanced out by 2 - of charge that is contributed by 2 BR minuses so that means the charge on chromium is 2 + and we can call this compound chromium now we need to say what its charge is and we do this using Roman numerals in parentheses so it's CR 2 + so we're going to use the Roman numerals for 2 so there's the 2 and now what do we call BR here well the negative
naming ionic compounds with transition metals practice problems
ion BR minus is called Boro me bromide the neutral compound is called bromine and so when it becomes a negative ion we change the ending to IDE so the neutral version is bromine and that changes to bromide so this is going to be chromium 2 bromide just a quick word of advice don't be confused with this - some students think that it's the number that should come after chromium here but that's not true the two refers to the charge on chromium let's look at a few more examples okay
au to s so au here is gold and gold is able to make two different types of ions gold can make au plus an au 3 plus so we got to figure out what charge this au has we'll focus in on s s is in this column of the periodic table which means that it always has a charge of 2 minus so here we got s 2 - now there's only one s there's no number after that s so that means that our total negative charge in the compound is 2 - from this one s 2 - here now for the positive charge the positive and
the negative has to balance so that means that over on this side we have to have 2 plus a positive charge now what's the charge on gold on a you well this 2 tells us that we have two gold ions in the compound here's one here's the other and this 2 plus is distributed between these two ions so that means that each one since we have two of them is going to be au 1 + so now we have 2 au 1 pluses give us 2 + of total positive charge balanced out by 2 minus of negative charge from our s 2
- so we've figured out in this case that our charge on gold is 1 + so we're going to call this gold and then we'll use the Roman numerals gold 1 in parentheses and for s when s is a negative ion s 2 - we call it sulfide as a neutral element it's called sulfur and then we add that I ve to the end of it when it becomes a negative ayah so again this one here in parentheses refers to the charge on gold it doesn't have anything to do with a number after gold all right let's do
a couple more Co 3 n 2 so Co here is cobalt and cobalt can make two different ions it can make CO 2 plus ion and a co 3 plus ion what is its charge here let's figure out we'll focus in on n which is in this column here which means that it's charged in an

ionic

compound is always in three - now what's the total negative charge here well this is n 2 which means that we have two of these so I'll add an extra one now we have two and this means that our total negative charge is 3
naming ionic compounds with transition metals practice problems
- plus 3 - which gives us 6 - now for the positive charge the positive and the negative has to balance out so that means that we have a total of 6 + over here now for cobalt CO we have three of them let me redraw them in here 1 2 3 so how are we going to divide up this 6 + amongst the 3 Cobalts will do it so that each one of them has to plus of charge and that means that in this chemical compound cobalt has a charge of 2 + so for

naming

it we'll call it cobalt Roman numerals here parenthesis
2 because that's its charge here and finally n 3 - we call that nitride the neutral element is called nitrogen and then we add that IDE cobalt to nitride let's do a couple more these might be a little bit more challenging so it's probably worth checking them out Zn oh alright this is kind of a trick question actually because Zn is one of the few

transition

metals

that can only make one type of ion it always makes a 2 plus ion because there's only one possible ion we don't
need to use those Roman numerals in the parenthesis so we just call this zinc oxide we don't call it as ink to oxide now there's one other element on the periodic table that's a

transition

metal that only makes one type of ion and that is silver which always makes AG 1 plus so if you're

naming

a compound that contains zinc or silver even though their

transition

metals

you don't need to use the Roman numerals because they can only make one type of ion now so far in all of our
examples the negative ion has been a single element bromide or sulfide or nitride but it's also possible for

transition

metals

to form

compounds

with polyatomic ions which are groups of atoms that together have a charge so I want to do one example where we have to figure out the charge on a

transition

metal that's in a compound with one of these polyatomic ions here's our last one V then parentheses co3 2 so the V here is vanadium which is a

transition

metal that's able to make
four different types of ions 2 plus 3 plus 4 plus and 5 plus now this Co 3 here is a polyatomic ion it's the polyatomic ion carbonate so how did I know that well obviously I wrote the question but this is a good example of when it makes sense for you to learn the polyatomic ions so that if you see them in a problem like this you can just recognize them right away so to figure out the charge on vanadium we need to focus in first on carbonate our negative ion so carbonate co 3 has a charge of
2 - OH co3 - - these parentheses and the two outside tell us that we have two of these carbonates so let me write another one in here Co three - - and that means that for total negative charge here we have four - now that for - has to be balanced out by four plus a positive charge and that positive charge is going to end up on this vanadium there is only one of them there's no number after it so there's just one so that means that this vanadium has to hold all of the positive charge so
it's vanadium 4 + so we're gonna call this compound vanadium now the Roman numeral for 4 might be a little bit unfamiliar to you it's AI V it's a good idea to memorize the Roman numerals at least up to 7 which is probably like the highest ion you're ever going to see so vanadium IV for 4 and then as we said this ion Co 3 - - is carbonate so the name of this compound is vanadium 4 carbonate this 4 is a charge on vanadium so that is how we take the formula for a compound that
contains

transition

metals

and how we write a name for it complete with these Roman numerals