Naming Ionics
Stepwise Method for Naming Ionic Compounds
1. Name the metal first (ie. NaCl, sodium chloride)
2. The name of the nonmetal has -ide added (ie: NaCl sodium chloride)
3. If the metal has more than one possible charge, we must indicate
which oxidation state (charge) is present using the Stock Method.
Indicate the ion by writing the charge in roman numerals
(ie: FeCl2 Iron (II) chloride).
Examples using the Stock Method
Compound
Stock Method
FeF2
iron (II) fluoride
FeF3
iron (III) fluoride
Hg2Br2
mercury (I) bromide
HgBr2
mercury (II) bromide
Polyatomics
Using a Polyatomic Ion to Determine the Charge on a Metal
Consider Fe(OH)2
1. Use the polyatomic ion to determine the charge of the metal, OH- is
-1, 2 OH-‘s in the formula therefore Fe must be +2
2. Name the metal using Stock Method, iron (II) (Fe)
3. Name the anion, hydroxide (OH-)
4. Name the compound, iron (II) hydroxide
Name of
Ion
Formula
Charge
cyanide
CN-
-1
sulfate
SO4-2
-2
phosphat
e
PO4-3
-3
carbonat
e
CO3-2
-3
chromate
CrO4-
-1
Hydrates (this is new! Please copy)
Many ionic compounds also have water
molecules attached to the formula;
these do not affect the name of the
ionic compound; however we must
have a way to account for them within
the name.
Number
Prefix
1
mono-
2
di-
3
tri-
We refer to them as hydrates. We
use the covalent prefixes to indicate
the number of H2O molecules present
in a hydrate. You will see this on the
CSI sheet you got last day!
Consider CuSO4.5H2O
4
tetra-
5
penta-
6
hexa-
7
hepta-
8
octa-
9
nona-
10
deca-
copper (II) sulfate pentahydrate
Covalent Molecules
***Covalent molecules are typically made up of two or more nonmetals and we cannot determine the number of atoms in a covalent
compound simply by naming the first and second element.***
For example: carbon (C) and oxygen (O) can combine to form CO and
CO2 (also CO32- but we will neglect this for the time being).
If we were to use the ionic naming system we would get for each case
carbon oxide, which does not tell the two molecules apart.
To this end we need to use the prefixes: mono, di, tri, tetra etc.
To name covalent compounds use the following method
prefix + first element + prefix + root of second element + ide
(the prefix "mono" is assumed, and therefore dropped)
Covalent Compounds
To name covalent compounds use the following method
prefix + first element + prefix + root of second element + ide
Exceptions:
Examples
1. H2O is water, not dihydrogen
oxide.
1. SO2 (sulfur dioxide)
2. NH3 is ammonia, not nitrogen
trihydride.
3. CO is carbon monoxide and
N2O is dinitrogen monoxide
but in all other cases, the
mono is dropped.
2. Si3P6 (trisilicon hexaphosphide)
3. BF3 (boron trifluoride)
4. CO2 (carbon dioxide)
5. S5F (pentasulfur fluoride)
Covalent Molecules
BF3, boron
trifluoride
PCl5, phosphorus
pentachloride
S4N4, tetrasulfur
tetranitride
Naming Acids - copy
An acid is a special kind of compound. When it is dissolved in water, an
acid releases a hydrogen ion (H+) into solution.
Even though many acids are made from two non-metals (H and F, Cl,
Br, I) we treat them as ionic compounds.
We can tell a compound is an acid by indicating its state:
o HCl(g) is hydrogen chloride gas
o HCl(aq) is hydrochloric acid because (aq) means aqueous or
dissolved in water
Naming Acids - copy
Rule 1 - To name an acid if it is binary
(having hydrogen and either F-, Cl-, Br- or I-)
hydro ________ic acid (fluor, chlor, brom, iod)
HBr(aq) is hydrobromic acid
Rule 2 - To name an acid with a polyatomic ion
Replace the suffix “ate” with “ic” and add “acid” to complete the name
Replace the suffix “ite” with “ous” and add “acid” to complete the name
HNO3 (aq) (hydrogen nitrate, becomes “nitric acid”)
HNO2 (aq) (hydrogen nitrite becomes “nitrous acid”)