Ch 5 - Ionic CompoundsCh 5 - Ionic Compounds

Naming & Writing Formulas

RememberRemember

• In an ionic compound– 1st element is a + metal ion– 2nd element is a – nonmetal ion

• Naming is EASY PEASY!– 1st element’s name doesn’t change– 2nd element’s name ends in –ide – Transition metals need to show Roman Numeral– polyatomic ions keep their own names

Naming Nonmetal AnionsNaming Nonmetal Anions

Transition Metals – Use Systemic NameTransition Metals – Use Systemic Name

What are Polyatomic Ions• Groups of elements that act as a group• The charge is on the entire group• NEVER change formula of polyatomic ions• Put them in parenthesis if need be.

is written as SO4 -2

Ex. compounds: BaSO4 Barium Sulfate Fe2(SO4)3 Iron III Sulfate

Common Polyatomic Ions

ExamplesExamples1. Regular

NaF – Sodium Fluoride

CaO – Calcium Oxide

2. Transitional MetalsFeCl3 – Iron III Chloride (Fe+3 because 3 Cl- in formula)

CuI – Copper I Iodide (Cu+1 because one I- in formula)

3. Polyatomic Ions

BaSO4 – Barium Sulfate

NH4OH – Ammonium Hydroxide

Mixed Practice

1.1. BaIBaI22

2.2. Ca(OH)Ca(OH)22

3.3. FeCOFeCO33

4.4. NaNa22CrCr22OO77

5.5. Cu(ClOCu(ClO44))22

1.1. Barium iodideBarium iodide

2.2. Calcium hydroxideCalcium hydroxide

3.3. Iron (II) carbonateIron (II) carbonate

4.4. Sodium dichromateSodium dichromate

5.5. Cupric perchlorateCupric perchlorate

Writing Ionic FormulasWriting Ionic FormulasCompounds are neutral: +ions & – ions have to balanceSteps

•Write the + ion first•Write the – ion second•Compare oxidation numbers (charges)

-If the same, you are done-If different, criss-cross as subscripts-Never change polyatomic ions (use parenthesis if needed)

Formula of Ionic CompoundsFormula of Ionic Compounds

Al2O3

Al3+ O2-

CaBr2

Ca2+ Br-

Na2CO3

Na+ CO32-

Try it out…Try it out…

• Write the formula for a combination of these ions:

Try it OutTry it Out

• Write the formula of these ionic compounds: