memorize. Okay, here is a simple strategy
that has helped my students remember how to name compounds correctly. The strategy
is to identify the type of compound from the very beginning. Whether it's ionic or
molecular. Molecular refers to covalent compounds. An ionic compound consists of
one metal and one nonmetal. A covalent compound consists of two nonmetals.
Looking at your periodic table the highlighted portion shows you all the
different types of nonmetals. Everything there after then is a metal. We'll
start with the different types of naming for ionic compounds. The first one, ionic
compounds without a transition metal. Aluminum Oxide shows you the name of the
metal, our aluminum, and oxygen, or our nonmetal, ending in "ide." Looking at the
periodic table we need to identify our charges, so if you have to pause the
video and write these down, these are the charges that you need to have memorized.
For ionic compounds you will always have to balance out your charges. For this
example aluminum oxide, let's identify the charges for aluminum and oxygen.
Aluminum's charge is a 3+ charge and oxygen has a 2-
charge. Aluminum had that 3+ charge and oxygen had the 2-. Let's balance
these charges out by multiplying our aluminum or, really, placing a subscript
of 2, that 2 then multiplies with our 3+ charge and it becomes a 6+
charge. We want these charges to be the exact same. So I'll also then place a 3
subscript, that would then turn this 2- to a 6- charge and our charges
are balanced. Another way of looking at this is to really "lasso," I've heard
that term before, our charges where our aluminum gets that 2 and oxygen then
gets the 3. They get the opposite charges of each other just so they can make the
same exact charge. They would then cancel out the charges and be neutral. And
our final balanced compound is aluminum oxide having that subscript of 2 and 3.
The second one is ionic compounds with a transition metal. This consists of the
name of our transition metal, a Roman numeral in parentheses, and a nonmetal
ending in "ide." Our transition metal is iron and our Roman numeral is 3. Your
Roman numeral actually tells you the charge of your transition metal. A lot of
times transition metals have different types of charges. Iron sometimes has a 2+ or a 3+ charge, so our Roman numeral actually tells us the charge of
what iron is, within this compound. Your nonmetal is the oxygen and once again
that ends in "ide." So we need to balance out our charges. Your iron as we saw was
a 3+ charge, your oxygen was a 2- charge. Balancing out these charges
we'll place a 2 subscript for our iron and a 3 subscript for the oxygen. We now
have these sixes canceling out, which is what we wanted, and your final compound
is Fe2O3. Polyatomic atoms just means that there
are two or more elements within that atom. Know these polyatomic atoms. Write
some flashcards. I will also place a link in the
description box of more polyatomic atoms that you should also know. Moving on to
ionic compounds with a polyatomic atom. They consist of the name of our metal
and our polyatomic atom. Notice that you do not have your nonmetal ending in "ide."
A lot of times polyatomic atoms end in "ate" or "ite" with the exception of
hydroxide and cyanide. We have calcium phosphate. Calcium is the name of our
metal and phosphate is our type of polyatomic atom. Polyatomic atoms do
have specific charges, so that is once again something you do have to know.
Calcium has a 2+ charge, phosphate has a 3- charge. Our phosphate
started off with having four oxygen. So to balance out our charges we need to
place this in parentheses to isolate that phosphate group. Doing so, we'll place our three with our
calcium, that'll once again give us a 6+ charge. We'll place our 2 on
the outside of parentheses. Polyatomic atoms tend to have parentheses whenever
we place a subscript. These are now balanced and your final compound is
calcium phosphate. This is how it's properly balanced. Our last ionic
compound mixes transition metals and polyatomic atoms. It consists of the name
of the transition metal, a Roman numeral, and the polyatomic atom. Here we'll see
Copper (II), once again that (II) tells us the charge of copper, which is our transition metal,
and our polyatomic atom of nitrate. Nitrate is NO3 and has a -1
charge. We saw that copper had that 2+ charge so all we need to do is just
have a 2 for our nitrate since copper is already 2. Balancing out our charges we'll
place this in parentheses and place our 2 subscript outside and we'll have
these twos cancel. Your final compound is copper nitrate with a 2 subscript
only on the nitrate. Let's start with going backwards now.
So instead of having the compound name we're given the formula and asked to
actually write the name of the compound. FeBr2, Fe is known as iron and Br is
known as bromine. Iron is a type of transition metal, bromine is a nonmetal.
So our nonmetal will end in "ide" and we know that a transition metal will have a
Roman numeral. To figure out what your Roman numeral is, let's go back to the
overall charges. So bromine is a type of halogen, just meaning that it has a -1 charge. So since this had a -1 charge, Fe or iron, must
have had a 2+ charge. Another way of identifying this, is if we were to go
backwards, this 2 would go back on to the iron, since bromine needed 2 to
balance out the charges altogether. So we'll have iron (II) bromide. Let's try
another example like that. Cu3(PO4)2. Cu is known as
copper. It is a type of transition metal so we have to have a Roman numeral. PO4
is a type of polyatomic atom. We had to know that polyatomic atoms
charge was a 3- because this then allows us to figure out that copper had
a 2+ charge. Another way of looking at this is, this 2 goes back to
the previous element. So that 2 belongs to the copper and this 3 then belongs to
our phosphate group. That's a trick that you can use whenever you're using your
formula and you're trying to go back to the actual name of the compound. So our
name of our compound would then be copper (II) phosphate. Those are all the
different types of combinations for ionic compounds. Moving on to covalent or
molecular compounds. Something that we have to know are the prefixes. Know 1
through 10 because you do not have to balance any of the charges, I repeat for
covalent compounds do not balance charges. Covalent compounds consists of
two nonmetals as we mentioned before. The setup will be that there is a prefix
plus the name of your nonmetal, next another prefix plus the name of your
nonmetal ending in "ide." Diphosphorus Pentoxide. You will also hear this as
Penta oxide. The most common form is pentoxide. Our subscript is that "Di" and
the "Pent." "Di" meaning two and "Pent" meaning five. Once again we do not have
to balance any charges. All you have to notice is the "Di" means two, so there are
two phosphorus. The "Pent" means five so there is five oxygen. That's it, you're
done no balancing charges. Your prefixes literally tell you how much of that
element there is. We have N3O6. We'll look at the different subscripts and figure
out what prefix they need. So our three meaning "tri" and six means "hexa." So we'll
put "tri" and then the name of our nonmetal which
was nitrogen, then we'll put "hexa" and the name of our other nonmetal ending in "ide."
So we have Trinitrogen hexaoxide. Now I hope you don't plan on leaving here
without practicing what you just learned. (Music) If you need more help, I will be doing
online tutoring every now and then, so sign up I'll place a link in the
description box. Now don't forget you, can learn absolutely anything. You want to be
a doctor, you can do it. You want to be a dentist, you can do it. And the secret to
learning anything is