Chemistry Ch. 9.2Chemistry Ch. 9.2

Naming and Writing Formulas Naming and Writing Formulas for Ionic Compoundsfor Ionic Compounds

Naming Binary Ionic CompoundsNaming Binary Ionic Compounds

Binary compounds are composed of Binary compounds are composed of two elements and can be either ionic two elements and can be either ionic or molecular.or molecular.

If you know the formula for a binary If you know the formula for a binary ionic compound, you can write its ionic compound, you can write its name.name.

Place the cation name first, followed Place the cation name first, followed by the anion name.by the anion name.

NaBr is sodium bromide. SrFNaBr is sodium bromide. SrF22 is is strontium flouride.strontium flouride.

CuO is not just copper oxide. Copper CuO is not just copper oxide. Copper can form 1+ and a 2+ cations. The can form 1+ and a 2+ cations. The formula indicates a 1 to 1 ratio. formula indicates a 1 to 1 ratio. Since oxygen is always 2-, the Since oxygen is always 2-, the correct name is copper(II) oxide.correct name is copper(II) oxide.

What is the formula for copper(I) What is the formula for copper(I) oxide?oxide?

CuCu22O.O.

Writing Formulas for Binary Ionic Writing Formulas for Binary Ionic CompoundsCompounds

Easy. Write the symbol of the cation Easy. Write the symbol of the cation and then the anion. Add whatever and then the anion. Add whatever subscripts are needed to balance the subscripts are needed to balance the charges.charges.

Calcium bromide. CaCalcium bromide. Ca2+2+. Br. Br--.. CaBrCaBr22

Use the crisscross method, and then Use the crisscross method, and then reduce to the lowest whole number reduce to the lowest whole number ratio if necessary. ratio if necessary.

Compounds with Polyatomic IonsCompounds with Polyatomic Ions

Again easy. Write the symbol for the Again easy. Write the symbol for the cation followed by the formula for the cation followed by the formula for the polyatomic ion, and then balance the polyatomic ion, and then balance the charges. Use crisscross method.charges. Use crisscross method.

CaCa2+2+ (NO (NO33))--

Ca(NOCa(NO33))22

Naming Compounds with Naming Compounds with Polyatomic IonsPolyatomic Ions

First, figure out if the compound First, figure out if the compound contains a polyatomic ion!contains a polyatomic ion!

If so, then to name the compound, If so, then to name the compound, simply state the cation first and then simply state the cation first and then the anion…the same as for binary the anion…the same as for binary ionic compounds.ionic compounds.

NaClO is sodium hypochlorite.NaClO is sodium hypochlorite. What is (NHWhat is (NH44))22CC22OO4 4 ??