Warm up 10-22-151. Name the following compounds:

CaCl2 S2F5

2. Write the chemical formula for these compoundsPotassium sulfideDiphosphorus tetrachloride

AgendaTurn in lab bondsTake Quiz Unit 4Notes Unit 4-4Practice WS Unit 4-4

HomeworkOct 24 – Academic SchoolOct 29 - Extra credit dueOct 30 - Online HW unit 4

Quiz Unit 4

2 questions - Finding Ions (positive and negative charge)

2 questions - Bonds (3 types)2 questions - Naming compounds (rule 1 & 2)

You will need a half sheet of paperRecord your quiz version #

Unit 4-4Lewis Dot structure

How do we determine which elements will combine to make

bonds?

Nomenclature: Ionic Compounds Transition Metal Examples

Regular metal CaCl2 = Calcium chloride

Na2S = Sodium sulfide

1. FeCl2

2. FeN3. Iron (I) nitride4. Iron (II) nitride

Answers1. Iron (II) chloride2. Iron (III) nitride3. Fe3N4. Fe3N2

Nomenclature: Ionic CompoundsPolyatomic Ions

(NH4)+ Ammonium (NH3) Ammonia

(OH)- Hydroxide(CO3)-2 Carbonate

(NO3)- Nitrate (NO2)- Nitrite

(SO4)-2 Sulfate (SO3)-2 Sulfite

(PO4 )-3 Phosphate (PO3)-3 Phosphite

(Cr2O7)-2 Dichromate

Naming Polyatomic Ions Examples

1. ______________ SrSO4

2. ______________ Ca(NO2)2

3. Ammonium Sulfide _____4. Potassium hydroxide _____

Strontium sulfateCalcium nitrite

(NH4)2SKOH

Naming Ionic CompoundsPractice

1. ______________ AlCl3

2. ______________ Na2S

3. Lithium Bromide _____4. Calcium Fluoride _____5. ____________ CuCl2

6. Iron (III) Phosphide ____

7. ______________ Li3PO4

8. ______________ Sr(NO3)2

Transitionmetal

Electron Distribution in Molecules

Electron Distribution in Molecules

• Electron distribution is depicted with Lewis structures (electron dot) showing valence electrons

• Show the number of bond in the covalent compound(In ionic bonds, it was decided with charges)

G. N. Lewis 1875 - 1946

Lewis Structures for Elements

1) Write the element symbol.2) Starting at the right, draw

4 electrons, or dots, one on each side around the element symbol.C

Lewis Structures

C

Try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

H

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

P

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Ca

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Ar

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Cl

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Al

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Bond FormationBond Formation

A bond can result from an overlap of atomic orbitals on neighboring atoms.

ClH H Cl••

••

••

••

••

••

+

Note that each atom has a single, unpaired electron.

H Cl••

••••

Bond and Lone Pairs

Bond and Lone Pairs

• Valence electrons are distributed as shared or BOND PAIRS and unshared or LONE PAIRS.

•• •

•

• •H Cl

lone pair (LP)shared orbond pair

This is called a LEWIS structure.

• •

• All atoms want to have 8 valence electrons (except H, only needs 2)

• Obtain a total of 8 by sharing • Only lonely electrons will share – pair of

electrons with existing partners will not share and make bonds

Sharing ElectronsSharing Electrons

Types of BondsTypes of Bonds

Single bond Cl2

Double bond = CO2

Triple bond N2

Draw C2H4

Draw H2O2

Example Lewis Dot for Compounds

Example Lewis Dot for Compounds

Draw CH4

• Lewis structure help predict molecular shape

Valence Shell Electron Pair Repulsion(VSEPR)

Valence Shell Electron Pair Repulsion(VSEPR)

Assignments

• Summary• Lewis dot worksheet (4-4) due next class