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in this video we're going to go over

the nomenclature of ionic compounds

particularly those that have polyatomic

ions and

transition metals

so you need to know the names of certain

polyatomic ions

so let's say if you have so3 2 minus

this is called sulfite

let's review some polyatomic ions

so4 2 minus

this is called sulfate

s2 minus is a monoatomic ion

and monoatomic ions they typically end

in ide instead of i or 8.

so this is called sulfide

what do you think the names

for these ions are

po4 three minus

is known as

phosphate

po3 three minus

is called

phosphite

eight usually has one more oxygen than i

and p minus three that's a monoatomic

ion

it's phosphide

what about these clo4 minus

clo3 minus clo2 minus

clo minus and cl minus

clo4 is called

perchlorate

clo3

is chlorate

clo2 minus is chlorite

clo minus is hypo

chlorite

and the monoatomic ion cl minus

is chloride with an ide

suffix

now there's some other ions that you

should know

feel free to pause the video and write

the names of these ions and see if you

have the correct answer

oh minus is known as

hydroxide

co32 minus

is called carbonate

no3 minus

is nitrate

no2 minus nitrite

which has one less oxygen than eight and

this is called acetate

see if you know these

cr042 minus is known as chromate

cr2o72 minus

is called a dichromate

mno4 minus is permanganate

and cn minus

is cyanide

and c2o2 minus is oxalate

now let's go over some examples let's

say

if you want to name the compound

nacl

how can you do

it so the first atom and a you simply

need to write the name

n a is known as sodium

now cl is chlorine but instead of saying

chlorine you want to say chloride

for the last part you need to add the

end in ide

so nacl is composed of sodium ions and

chloride ions

here we have a monoatomic anion

and cl minus is known as chloride

now let's say if we want to name kclo3

the first element k is simply called

potassium

the second part the polyatomic ion you

simply just need to know what the name

is

clo3 is called chlorine so this is

potassium chlorate

go ahead and write the names

of the following compounds

so what's the first one

the first element n a is called sodium

and co3

is the carbonate polyatomic ion so this

is called sodium

carbonate

for the second one mg

is magnesium

and we simply have s which is a

monoatomic ion so it's going to have the

end in ide

so it's magnesium sulfide

ba is known as barium

and so4 two minus is a polyatomic ion

called sulfate

so it's barium sulfate

and the last one

a l

is aluminum

and the o h part

is hydroxide so combined it's simply

aluminum hydroxide

well i'm sure by now you must be saying

to yourself it can't be that easy

and there are some harder examples

particularly with the transition metals

where you have multiple oxidation states

for example

how would you name

fecl2

and fecl3

now it turns out that fecl2

is called iron

to

chloride

and it's not necessarily because

there's a two here

what it really represents

is the oxidation state or the charge on

fe

now chlorine as an ion has a negative

one charge

and because of the subscript there's two

chloride ions

so fe

needs to have a charge

that balances those two negative charges

the total negative charge is negative

two and we only have one fe particle so

it has to have a charge of plus two

to neutralize the total negative two

charge

by the two chloride ions

so therefore it's called rn2 chloride

fecl3

is known as iron iii chloride

because the charge on iron

is plus three

it has to have a charge of plus three to

neutralize

the

three chloride ions which has a net

charge of negative three

and so that's how you can write

the name

for

an ionic compound that has a transition

metal with multiple oxidation states

you need to use the roman numeral to

specify

the charge of the metal

so let's go over the roman numeral

system

this represents one

this number is two

and this number is three

now if you see a v

v represents five

now if you see like an i that's to the

left of the v

that means five minus one which is

really four

now if you see an i symbol to the right

of the v instead of the left

it's five plus one which correlates to

six

and if you see this that's five plus two

which is seven

now let's go back to fe

how would you name

fes

and

fe 2 s3

now notice that the coefficient is 1 but

it's not rn1 sulfide it turns out

this is called rn2 sulfide

and the reason for that

is because the charge on sulfur is

negative two

and therefore the charge on f e must be

plus two to balance it because

they exist in a one to one ratio

now if you seem confused by this

you can write an equation to solve for

the oxidation state of f e

so it's going to be f e plus s is equal

to zero

the zero comes from the fact that the

net charge of this compound is zero it's

neutral overall

now to find the answer

to solve for f e you need to know the

charge on sulfur

so you need to know the common charges

of the monoatomic ions

sulfur has a charge of negative two when

it's the most electronegative element in

the compound

so to solve for fe you need to add two

to both sides and you can see that

f e has a charge of plus two

so now what about the example on the

bottom

what is the oxidation state of fe in fe2

s3

so let's write an equation 2fe

plus 3s

is equal to 0.

the charge on sulfur we know it to be

negative two

so three times negative two

is negative six

and let's add six to both sides

so at this point

we can see that

two f e

is equal to positive 6.

so if we divide both sides by 2

f e

has a charge of 6 divided by 2 which is

plus 3.

so it's in the plus 3 oxidation state

so now we can write the name of the

compound so we know it's iron

3

sulfide

since fe has a plus 3 charge

sometimes the oxidation state is going

to be this number sometimes it's not

so don't always rely on it but it's a

possible it's an indicator that it could

be plus three

just not all the time

now let's go over the charges of certain

monatomic ions

the group one metals like sodium

lithium potassium

even hydrogen

which is a non-metal

the elements in the first column

typically form

ions with a plus one charge

the elements in the second column

like calcium

magnesium strontium

these two

or three they form charges

that are of the plus two magnitude since

they have two valence electrons by the

way lithium is above sodium so i really

didn't put this in order

then in group 3a which is like group 13

on the periodic table

you have elements such as aluminum

gallium

and these guys they form

ions with a plus three charge

now the group 4a elements

such as silicon

germanium

10

lead

typically they form plus two and plus

four oxidation states

and then you have elements like nitrogen

and phosphorus

these elements like most non-metals they

like to acquire electrons so they like

to form

ions with a negative three charge and

then you have the calcagens like oxygen

sulfur and selenium

they like to form a minus two charge and

then the halogens

which are very reactive non-metals like

fluorine

chlorine

bromine and iodine

they form negative one

charges

so knowing that information can help you

to determine the oxidation state

of

a transition metal

so let's try

these examples

name

pbo and pbo2

so pb stands for lead

o is oxide as a monoatomic ion

so we have lead oxide

we just need to know what the oxidation

status for this particular substance

so if we write an equation pb plus

oxygen equals a net charge of zero

we know that oxygen has a charge of

negative two

so if we add two to both sides we can

see that pb

is in the plus 2 oxidation state

therefore to name it

it's going to be called

lead

2

oxide

so now what about the other compound

well let's write an equation

so we have pb plus two oxygen atoms

is equal to zero

so let's replace o with negative two

two times negative two is negative four

and if we add four to both sides

pb is in the plus four oxidation state

so therefore to name it

it's going to be called

lead

for

oxide

try this one

let's see

v3

p5

and

sn

3

po4

four

so feel free to pause the video and try

those examples

so v is vanadium p is phosphorus but

p is going to be the phosphide ion so we

have vanadium phosphide but we got to

find the oxidation state

so let's write an equation 3v

plus 5p

is equal to 0.

now phosphorus as an ion has a negative

three charge

it's in group 5a of the periodic table

so 5 and negative 3 is negative 15.

so if we add 15 to both sides 3v is

equal to plus 15.

and then if we divide by three

vanadium is in the plus five oxidation

state

so to name it

it's going to be called

vanadium

5

phosphide

so let's try our last example

sn is 10 p.o force phosphate so let's

calculate the oxidation state

so we have 3sn

now you want to view phosphate as a

single unit because you know the overall

charge

so we have four phosphate units

and the net charge is zero

so phosphate as a polyatomic ion has a

net charge

of minus three

so four times negative three is negative

12. if we add 12 to both sides we get

this

and our last step is to divide by three

so therefore 12 divided by 3 is 4.

so 10

is in the plus 4 oxidation state

so now we can write the name

so it's going to be called

tin

for

phosphate

so now you know how to name ionic

compounds that contain transition metals

and even polyatomic ions