Chapter 6Lesson 3 (Part I)

“Names and Formulas for Ionic Compounds”

I. Oxidation Charges

A. Def – a positive or negative number assigned to an atom or compound.1. Use the Periodic Table2. Ex: Lithium

a. Li loses 1 electron and becomes 1+3. Ex: Fluorine

a. F gains 1 electron and becomes 1-

II. Binary Compounds

A. Def – composed of 2 elements1. Ex: Sodium Chloride (NaCl)2. Groups 1-8 have set oxidation numbers. (1, 2, 3, -3, -2, -1, 0)

B. Multiple Oxidation Numbers1. Transition Metals

a. Use Roman numerals to represent charge

-Ex: Cu (II) = -Ex: Cu (III) =

Cu2+

Cu3+

*Metals always have a positive charge / lose electrons

III. Writing FormulasA. 4 step system

1. Write the Symbol with positive oxidation #2. Write the Symbol with negative oxidation #3. Done if superscripts equal zero. If unequal #4 4. Criss Cross Method

B. Ex: Chlorine and Sodium combine

Na1+ + Cl1- =‘s 0

Oxidation numbers equal zero

NaCl

C. Sodium combines with oxygen1. Na1+ + O2-

rule #4

Na O2-1+

Criss Cross

Na2O

*oxidation numbers equal zero

Drop the superscript charges

Examples

1. Sodium Fluoride2. Calcium Chloride3. Aluminum Oxide4. Iron (II) Chloride5. Iron (IV) Bromide6. Copper (II) Nitride7. Magnesium Oxide8. Mercury (I) Nitride

IV. Naming Binary Compounds

A. 4 step system1. Write the name of the 1st element2. Write the “root” name of the second element.3. Add “ide”4. Check for Transition Metals

B. Ex: CaCl21. Calcium Chlor ide

2. ExamplesK3N

Al2S3

Mo2O

FeCl3ZnF2

V. Polyatomic IonsA. Def – having many atoms

1. Works as a covalent group2. Have a single charge (usually negative)3. List of Polyatomic Ions – pg. 173

B. Naming1. Write name of positive ion2. Write name of negative ion3. Check for Transition Metal 4. Ex: NaNO3Sodium + Nitrate

C. Writing the formula1. Write symbol of positive ion2. Write symbol of negative ion3. Check oxidation #’s to see if they equal zero4. Criss Cross Method

-Use parenthesis to “set apart” a polyatomic ion when more than one is needed.5. Ex: Write the formula for calcium nitrate.

Ca NO32+ 1-( ) Ca(NO3)2

Reminders with Transition Metals For naming compounds with

transition metals always include the Roman Numeral.

To determine the oxidation number of a transition metal in a formula add up all charges of the opposite ion.

Chemical formula do not need Roman Numerals.

Chapter 6Lesson 3 (Part II)

“Names and Formulas for Molecular (Covalent)

Compounds”

• Common prefixes• Only use with non-metals• Pg. 175• **Do not use ionic charges!!!

**

PrefixPrefix NumberNumber

Mono-Mono- 11

Di-Di- 22

Tri-Tri- 33

Tetra-Tetra- 44

Penta-Penta- 55

Hexa-Hexa- 66

Hepta-Hepta- 77

Octa-Octa- 88

Nona-Nona- 99

Deca-Deca- 1010

VI. Naming Molecular Compunds

A. Rules1. Most metallic element listed 1st

2. Prefix + element name3. Prefix + element name + add “ide”

B. Ex:N2O4

Nitrogen OxygenDi TetraOxide

B. Name the following molecular compounds.1. CO2. H2O

3. NO4. N2O

5. C4H8

6. Br2F8

7. P2O5

C. Writing Formulas for Molecular Compounds1. Use the prefixes for each element and convert them to subscripts2. Ex: Tetraiodine nonaoxide

= I4O9

3. Ex: Dicarbon pentafluoride= C2F5

D. Write the formulas for the following molecular compounds1. Carbon Dioxide2. Sulfur Hexafluoride3. Phosphorus Tribromide4. Diphosphorus pentaoxide5. Carbon Heptaoxide6. Dicarbon decafluoride