Naming Compounds
Ionic Compounds
• The net (final) charge of the compound will
be ZERO!
• This means that there must be equal
amounts of positive and negative charges –
not necessarily always equal charges on the
ions.
Naming ions
• Metal ions have their original name
• Metals with multiple oxidation numbers (possible charges)
will need to include the specific oxidation number
– Iron (II) or Tin (IV)
• Non-metals keep the same base name, but change the
ending to “ide”
– Chlorine becomes chloride
– Sulfur becomes sulfide
Practice Naming
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KCl
potassium chloride
Mg3N2
magnesium nitride
CuI
Copper (I) iodide (copper has +1 charge)
FeO
Iron (II) oxide (iron has +2 charge)
Writing Chemical Formulas
• Total Charge must equal zero
• If there is only one of the atom, not subscript
number is given - NaCl
• Formulas are typically written in reduced form
(H2O not H12O6)
• Shortcut – sometimes you can simple take the ion
charges and put them as the subscripts of the other
elements
– Fe+3 + O-2 -> Fe2O3
Practice Writing Formulas
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magnesium chloride
Mg+2 + Cl -1 -> MgCl2
sodium phosphide
Na+1 + P-3 -> Na3P
barium nitride
Ba+2 + N-3 -> Ba3N2
copper (II) iodide
Cu+2 + I-1 -> CuI2
Polyatomic Ion Names
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Ammonium
Sulfate
Carbonate
Nitrate
Chlorate
Cyanide
Bicarbonate
Hydroxide
Peroxide
Phosphate
NH4+1
SO4-2
CO3-2
NO3-1
ClO3-1
CN-1
HCO3-1
OH-1
O2-2
PO4-3
Naming with Polyatomic Ions
• Metals are named as usual
• Polyatomic ions use their specific names
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NO3 – nitrate
NO2 – nitrite
OH – hydroxide
SO4 – sulfate
• Name simply combines ion names
– MgSO4 is magnesium sulfate
• If more than one polyatomic ion is needed, it is put in
parenthesis and given a subscript
– Mg(OH) is magnesium hydroxide (two hydroxides needed)
Practice Writing Names with
Polyatomic Ions
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KClO3
potassium chlorate
Mg(NO3)2
magnesium nitrate
Na2SO3
sodium sulfite
Fe2(CO3)3
Iron (III) carbonate (iron has +3 charge)
Practice Writing Formulas
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magnesium phosphate
Mg+2 + PO4-3 -> Mg3(PO4)2
sodium peroxide
Na+1 + O2-2 -> Na2O2
ammonium nitride
NH4+1 + N-3 -> (NH4)3N
copper (II) hydroxide
Cu+2 + OH-1 -> Cu(OH)2