Chemical Nomenclature 3 Systems of Naming Compounds

Chemical Nomenclature

3 Systems of Naming Compounds

Traditional System

• Name the metal first; use Latin names of metals.• In binary compounds the nonmetal takes the suffix –ide.

• Some transition metals (electrons in d orbitals) can form more than one ion

• The ion with the lower charge takes the suffix

–ous• The ion with the higher charge takes the suffix –ic.

Traditional system II

• Element Lower chg Higher Chg.

• Copper Cuprous +1 Cupric +2

• Iron Ferrous +2 Ferric +3

• Nickel Nickelous Nickelic

• Manganese Manganous Manganic

• Mercury Mercurous Mercuric

Traditional system III

• How can you tell which ion is present?• Determine the charge on the nonmetal species, and the

charge on the metal which balances the negative charge on the nonmetal will reveal which ion is present.

• FeSO4 Ferrous or Ferric?– Fe+2 + SO4

-2

– Ferrous sulfate– What will be the formula of Ferric sulfate?– Fe2

+3(SO4)3-2 The – charge on sulfate does not change,

only the charge on the + ion has changed. The formula for the compound is changed accordingly.

Traditional system IV

• Cu2CO3

• Cuprous or cupric carbonate?

• Cuprous, Charge of +1 on the copper ion means 2 ions must neutralize –2 charge on carbonate

• Formula for cupric carbonate?

• CuCO3

Stock system

• Instead of Latin names and suffixes to indicate which ion is present, Roman numerals and modern names are used.

• Cu2CO3

• Copper (I) carbonate

• CuCO3

• Copper (II) carbonate

• Use the same system for any transition metal which forms more than one ion.

Prefix systemUse the following prefixes to denote how many ions or atoms are present

• 1 mono-• 2 di-• 3 tri-• 4 tetra-• 5 penta-• 6 hexa-

• 7 hepta-• 8 octa-• 9 non-• 10 deca-• 12 dodeca-

Prefix system

• Monocopper monocarbonate• CuCO3

• Most often the mono- prefix is understood in the same way as a subscript of 1 is understood

• Dicopper carbonate• Cu2CO3

• Dialuminum trioxide• Al2O3

• All you have to do is count.

Comparison of Nomenclature systems

Formula Traditional system

Stock system

Prefix system

Fe2(SO4)3 Ferric sulfate

Iron (III) sulfate

Diiron trisulfate

Cu3(PO4)2 Cupric phosphate

Copper (II) phosphate

Tricopper diphosphate

Assignment

• Answer questions 13-20 p. 170

• What movie for Friday??