


Groups of atoms that tend to stay together
and carry an overall ionic charge
eg.
NO3-
SO42-
These behave exactly like simple ions to
produce a compound with an overall charge of
zero
Polyatomic Ion
Nitrate
Formula
NO3-
Ionic Charge
-1
Carbonate
Chlorate
Sulfate
CO32ClO3SO42-
-2
-1
-2
Phosphate
Hydroxide
Ammonium
PO43OHNH4+
-3
-1
+1
“Nich Carsulpho”
“Nick the Camel ate a Clam Supper in Phoenix”
When polyatomic ions are associated with a
they form
1.
2.
Write the name of the first element (the
positively charged ion)
Write the name of the polyatomic ion
In the case of the polyatomic
ammonium, it is written first because it is
the positive ion!
THE POSITIVE ION ALWAYS COMES FIRST!
Name the following compounds:
1. Na2SO4
_______________________
2.
K2CO3
_______________________
3.
NH4NO3
________________________
4.
Fe3(PO4)2
________________________
5.
Al(OH) 3
_________________________
1. Write the symbol of the metal and the
polyatomic group. Place brackets around the
polyatomic.
2. Write ionic charges for the metal and polyatomic
group.
3. Cross over to get the subscript.
4. Simplify, if necessary. (YOU MUST BE
CAREFUL NOT TO REDUCE THE
POLYATOMIC GROUP!)
Example: sodium sulfate is _________
calcium hydroxide is _________
Write the chemical formulas for the following
compounds:
1.
sodium carbonate
_______________________
2.
magnesium nitrate
_______________________
3.
sodium hydroxide
_______________________
4.
copper(II) sulfate
_______________________