1. 3-4 polyatomic ions (section 5.5)
And you

2. “Poly” means “many” and “atomic” refers to atoms
“Poly” means “many” and “atomic” refers to atoms. Polyatomic ions are 2 or more atoms covalently bonded to each other with an overall charge (hence the ion).

3. The following common polyatomic ions names and formulas must be memorized:  
NH4+1
ammonium
PO4-3
phosphate
NO2-1
nitrite
HPO4-2
hydrogen phosphate
NO3-1
nitrate
H2PO4-1
dihydrogen phosphate
SO3-2
sulfite
CO3-2
Carbonate
SO4-2
sulfate
HCO3-1
hydrogen carbonate (bicarbonate)
HSO4-1
hydrogen sulfate (bisulfate)
MnO4-1
permanganate
OH-1
hydroxide
O2-2
peroxide
CN-1
cyanide
Cr2O7-2
dichromate
C2H3O2-1
acetate
CrO4-2
chromate

4. Really! You need to know them!
I suggest making flash cards to help
And studying them prior to every test
Really!
I am not kidding here!

5. Names of cmpds. w/ polyatomic ions
Simply write the name of the polyatomic ion.
 Na2SO4 =
Sodium sulfate
LiNO3 =
Lithium Nitrate
Ca3(PO4)2 =
Calcium phosphate

6. HCN =
hydrogen cyanide
Na2CO3 =
Sodium carbonate
HOH =
hydrogen hydroxide
Great Job!!!!!!!!

7. Formulas from names w/polyatomic ions
Write the metal with its charge and the nonmetal with its charge (either could be a polyatomic).
Balance the charges.
The sum of charges for an ionic compound must = zero!

8. Examples Calcium carbonate = Ca+2 + CO3-2 = CaCO3 Ammonium nitride =
NH N-3 =
(NH3)3N

9. Magnesium sulfate =
Mg SO4-2 =
MgSO4
Aluminum nitrate =
Al NO3-1 =
Al(NO3)3

10. Fantastic!!!!! Silver Phosphate = Ag+ + PO4-3 = Ag3PO4
Ammonium hydroxide =
NH OH- =
NH4OH
Fantastic!!!!!