How to Name Chemical Compounds In order to apply the proper nomenclature to chemical compounds, the compound itself needs to be identified as to type or class

Question #1 What type of compound is it? Ionic? Molecular? - Organic? Acid? Hydrate?

Identifying the Compounds Ionic – usually a compound composed of a metal & a nonmetal; a metal & a polyatomic anion; a polyatomic cation and a nonmetal; or a polyatomic cation & a polyatomic anion. Molecular – usually a compound composed of two nonmetals -organic compound (one containing carbon and frequently hydrogen; excludes CO, CO2, and carbonates)

Identifying the Compounds Inorganic acids – these compounds contain hydrogen available for donation in a chemical reaction; their formulas generally start with H (hydrogen) and are followed by a nonmetal or polyatomic anion Hydrated compounds – these compounds appear as a salt or ionic compound with water molecules attached; meaning there is a dot (•), possibly a numerical coefficient, and the formula of water, H2O

Ionic Compound - Question #1 What is the positive ion? Metal from Group 1 (IA), Group 2 (IIA), Group 13 (IIIA) {first three elements} or Zn, Cd, or Ag? A metal not found in Group 1 (IA), Group 2 (IIA), Group 13 (IIIA) {first three elements} or Zn, Cd, Ag? A positive polyatomic ion?

Naming Positive Ions For metals from Group 1 (IA), Group 2 (IIA), or Group 13 (IIIA) {first three elements} Zn, Cd, or Ag Merely write the name of the metallic element e.g. K write potassium e.g. Al write aluminum e.g. Zn write zinc e.g. Ba write barium

Naming Positive Ions For metals NOT found in Group 1 (IA), Group 2 (IIA), Group 13 (IIIA) {first three elements} or Zn, Cd, Ag Traditional name – apply an “-ic” suffix to the ion of greater charge and an “-ous” suffix to the ion of lesser charge. Stock System name – place a Roman numeral in parentheses, ( ), immediately after the element’s name. The Roman numeral indicates the charge on the metal ion in that compound.

Naming Positive Ions Examples Fe+3 traditional name is ferric and the Stock name is iron(III) Cr2+ traditional name is chromous and the Stock name is chromium(II) Ni+2 only has a Stock name of nickel(II) Pb4+ traditional name of plumbic and a Stock name of lead(IV)

Identifying the Charge on the Cation In order to apply the Stock or traditional name, the charge on the metallic cation must be determined. How???? 1) Determine total negative charge in formula of the compound 2) Recognize, there is equal positive charge 3) Divide the positive charge by number of metal ions

Example FeO 1 x O-2 = -2 therefore +2 ÷ 1 Fe means it is Fe2+ called ferrous or iron(II) Fe2O3 3 x O-2 = -6 therefore +6 ÷ 2 Fe means it is Fe+3 called ferric or iron(III)

Naming Positive Ions In this case, ammonium for the NH4+ ion For polyatomic cations Write the polyatomic ion’s name In this case, ammonium for the NH4+ ion

Ionic Compounds - Question #2 What is the negative ion? Nonmetal – elements located to the right of the staircase on the periodic table A negative polyatomic ion Memorized from list

Naming Negative Ions For a polyatomic anion - For a nonmetallic anion – modify the name of the nonmetallic element with the attachment of an “-ide” suffix e.g. O-2 is called oxide e.g P3- is called phosphide For a polyatomic anion - Write the name of the polyatomic ion.

Examples LiBr lithium bromide CuCl2 cupric chloride or copper(II) chloride AgNO3 silver nitrate

SnO stannous oxide or tin(II) oxide Li3PO4 lithium phosphate (NH4)2S ammonium sulfide BaSO3 barium sulfite