IPC Notes
Polyatomic Ion Names &
Formulas
Polyatomic Ions
A polyatomic ion is a charged
covalently bonded group of atoms.
ex) sulfate is SO4-2
Common Polyatomic Ions
Nitrate = NO3-1
Sulfate = SO4-2
Phosphate = PO4-3
Ammonium = NH4+1
Carbonate = CO3-2
Hydroxide = OH-1
Common Polyatomic Ions
Nitrate = NO3-1
Sulfate = SO4-2
Phosphate = PO4-3
Ammonium = NH4+1
Carbonate = CO3-2
Hydroxide = OH-1
NOTE: There are
many more
polyatomic ions
that this short list.
You will use about
30 of them in
Chemistry.
Writing Formulas
1) Write the symbol of the first ion
with its oxidation number.
2) Write the symbol of the second
ion with its oxidation number.
Writing Formulas
3) Criss cross the numbers, not the + or –
sign.
4) If a subscript needs to be used with a
polyatomic ion, write parenthesis around
the polyatomic ion first and then put the
subscript at the bottom right.
Writing Formulas
Write the formula for:
aluminum sulfate
Writing Formulas
Write the formula for:
potassium nitrate
Writing Formulas
Write the formula for:
calcium phosphate
Writing Formulas
Write the formula for:
magnesium hydroxide
Writing Formulas
Write the formula for:
calcium carbonate
Writing Formulas
Write the formula for:
ammonium phosphate
Writing Names
1) Write the name of the first ion.
2) Write the name of the second ion.
If the second ion is a polyatomic
ion, leave the name alone. If the
second ion is just an element,
change the ending to –ide.
Naming Compounds
Write the name for:
MgSO4
Naming Compounds
Write the name for:
KNO3
Naming Compounds
Write the name for:
Al2(CO3)3
Naming Compounds
Write the name for:
NH4F
Naming Compounds
Write the name for:
NH4NO3
Naming Compounds
Write the name for:
Ca(OH)2