Polyatomic Ions and Compounds

Have You Ever…

Heard of things like sodium bicarbonate or sodium hydroxide?

How about baking soda or lye

Polyatomic Ions

Do not exist on the periodic table

Are special groups of elements

Multiple elements that group together and react as one

Polyatomic Ions – Do NOT Copy

Name of Polyatomic Ion

Formula Ionic Chage

AMMONIUM NH4 1+

NITRATE NO3 1-

HYDROXIDE OH 1-

BICARBONATE HCO3 1-

CHLORATE ClO3 1-

CARBONATE CO3 2-

SULFATE SO4 2-

PHOSPHATE PO4 3-

Naming Polyatomic Compounds

1. Write the name of the cation (usually the metal or NH4)

2. Write the name of the anion (usually the polyatomic group)

E.G.

Ca(OH)2

Na2SO4

(NH4)2O

Naming Polyatomic Compounds

1. Write the name of the cation (usually the metal or NH4)

2. Write the name of the anion (usually the polyatomic group)

E.G.

Ca(OH)2 calcium hydroxide

Na2SO4

(NH4)2O

Naming Polyatomic Compounds

1. Write the name of the cation (usually the metal or NH4)

2. Write the name of the anion (usually the polyatomic group)

E.G.

Ca(OH)2 calcium hydroxide

Na2SO4 sodium sulfate

(NH4)2O

Naming Polyatomic Compounds

1. Write the name of the cation (usually the metal or NH4)

2. Write the name of the anion (usually the polyatomic group)

E.G.

Ca(OH)2 calcium hydroxide

Na2SO4 sodium sulfate

(NH4)2O ammonium oxide (if it is a non-metal –

“ide”)

Writing the Chemical Formula of a Polyatomic Compound

1. Write the symbol of the cation

2. Write the symbol of the anion

3. Write the charge of each (the element and the group)

4. Criss-cross the charge # to the bottom

5. Re-write and reduce if needed

Examples

1. Calcium Nitrate

2. Beryllium Carbonate