The Name Game: Ionic Compounds

1. The cation comes first in the name (and in the formula) and it retains the name of the element.

2. If the compound contains a transition metal cation, the oxidation number of the cation is indicated in parentheses in roman numerals.Ex: Au3+ gold(III)

3. The name of the anion is changed so that it ends in -ideEx: chlorine chloride, oxygen oxide

AuCl3 Gold(III) chloride

PbO2 Lead(IV) oxide

Metals in Group 14 can often have more than one oxidation number

Na3N Sodium nitride

PbBr2 Lead(II) bromide

Now, you try some...

AgF Silver(I) fluoride

Al2S3 Aluminum sulfide

MgCl2 Magnesium chloride

FeCl3 Iron(III) chloride

TiO2 Titanium(IV) oxide

Polyatomic ions are made of more than one atom AND carry a charge.

1 P + 4 O + 3 e- PO4 -3

Whenever you are writing a formula with a polyatomic ion, imagine that it is surrounded by a force field that prevents the atoms in the ion from separating.

Phosphate ion

Polyatomic ions that you need to know are:

PO4-3

SO4-2

CO3-2

NO3-1

ClO3-1

OH-1

C2H3O2-1

NH4+1

Phosphate

SulfateCarbonate

NitrateChlorate

HydroxideAcetate

AmmoniumPg 619

The key to success is recognizing the polyatomic ions.

NH4Cl

NH3

Na4C

Na2SO4

Na2S

NaNO3

SO2

CO2

MgCO3

NaCl

NaClO3

NaOH

NH4OH

H3PO4

PCl3

AuPO4

AuP

Au2O

Some ionic compounds with polyatomics…

Aluminum and nitrateAluminum and nitrate

Al+3 NO3-1

Ammonium and carbonateAmmonium and carbonate

Al(NO3)3

NH4+ CO3

-

2

NO3-

NO3-

NO3-

Al+3

Aluminum and phosphateAluminum and phosphate

Al+3

PO4-3

Al+3 PO4-3

AlPO4

Ionic compounds are called formula units, NOT molecules.

Ionic compounds are called formula units, NOT molecules.

CO3-2NH4

+

NH4+

(NH4)2CO3

Now you try some…Now you try some…

Write the formulas for the following combinations

1. Sodium and phosphate

2. Ammonium and sulfur

3. Carbonate and silver(I)

4. Hydroxide and zinc(II)

5. Phosphate and iron(II)

6. Ammonium and carbonate

7. Gold(III) and acetate

Na3PO4

(NH4)2S

Ag2CO3

Zn(OH)2

Fe3(PO4)2

(NH4)2CO3

Au(C2H3O2)3

Naming ionic compounds containing polyatomic ions

1. The cation comes first in the name (and in the formula) and it retains the name of the element or the ion if ammonium.

2. The polyatomic anion retains its name.

Ex: CaSO4 would be calcium sulfate

NH4Cl

NH4ClO4

would be ammonium chloride

would be ammonium perchlorate