Naming IonicsNaming 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 MethodExamples using the Stock Method

Compound Stock Method

FeF2 iron (II) fluoride

FeF3 iron (III) fluoride

Hg2Br2 mercury (I) bromide

HgBr2 mercury (II) bromide

PolyatomicsPolyatomicsUsing 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

phosphate

PO4-3 -3

carbonate

CO3-2 -3

chromate

CrO4- -1

Hydrates (this is new! Please copy)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.

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!

Number Prefix

1 mono-

2 di-

3 tri-

4 tetra-

5 penta-

6 hexa-

7 hepta-

8 octa-

9 nona-

10 deca-

Consider CuSO4.5H2O

copper (II) sulfate pentahydrate

Covalent MoleculesCovalent Molecules***Covalent molecules are typically made up of two or more non-metals 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 CO3

2- 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 CompoundsCovalent Compounds

To name covalent compounds use the following method

prefix + first element + prefix + root of second element + ide

Examples

1. SO2 (sulfur dioxide)

2. Si3P6 (trisilicon hexaphosphide)

3. BF3 (boron trifluoride)

4. CO2 (carbon dioxide)

5. S5F (pentasulfur fluoride)

Exceptions:

1. H2O is water, not dihydrogen oxide.

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.

Covalent MoleculesCovalent Molecules

PCl5, phosphorus pentachloride

BF3, boron trifluoride

S4N4, tetrasulfur tetranitride

Naming Acids - copyNaming 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 - copyNaming Acids - copyRule 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”)