Catalyst – October 8-3, 2010

Label each of the following compounds/descriptions as either IONIC (I) or COVALENT (C).

1. NaBr2. Low melting point3. Good conductor, crystal4. NO2

5. Electrons shared

Today’s Agenda

Catalyst Multiple Covalent Bonds Pause for Environmental

Issues/Activist Letters…DHMO...Oh no!

Let’s see what you know…Naming Covalent Compounds

Work Time Exit Question

At the end of class…

You will receive… Quizzes Project Grades Progress Reports

Quiz Averages… 3rd Period: 82 4th Period: 80 (without curve: 70)

Today’s Objectives

SWBAT draw Lewis Dot Structures for covalent compounds with multiple covalent bonds.

SWBAT name and write formulas for covalent compounds.

Multiple CovalentBonds

LDS and Multiple Covalent Bonds

Key Point #1: Sometimes atoms must share more than one pair of electrons in order to become stable.

This results in double and triple bonds.

Double and Triple Bonds

Double covalent bond: two pairs of shared electrons (four electrons)

Triple covalent bond: three pairs of shared electrons (six electrons)

=

=

Strengths of Bonds

TripleDoubleSingle

Key Point #2: Bond strength increases with number of bonds.

So….a double bond is stronger than a single bond, and a triple bond is stronger than a single or double bond.

Example: Oxygen

Two oxygen atoms show up at the Homecoming Dance. Each oxygen atom has $6, but it costs $8 per atom to go inside. The School of Elements is offering a discount for couples. It costs only $12 for a couple atoms to go inside. How can both atoms get inside if they each only have $6???

They can share…electrons that is!!!

Try this one: Nitrogen

Two nitrogen atoms show up at the Halloween Party. Each nitrogen atom has $5, but it costs $8 per atom to go inside. The School of Elements is offering a discount for couples. It costs only $10 for a couple atoms to go inside. How can both atoms get inside if they each only have $5???

Model the bond formation of this happy couple!

Steps for Multiple Bond LDS’s

1. Write formula2. Number of valence

electrons (ve-)3. Number of octet

electrons (oe-) 4. Number of bonds5. Draw!

More Examples

O2

CO2

COCOCl2

Catalyst! Draw the covalent bond formation for these atoms

CS2

NOBrExtra: SO2 C2Br6 Se2

SiSBr2

Practice Time!

1. SO2

2. C2Br6

3. Se2

4. SiSBr2

5. Ge2H4

6. OS

The Environment…

In this class, I want you to learn the contents of basic chemistry…

However, I also want you to be able to understand the importance of chemistry in the environment.

There is a chemical, DHMO, that is especially ruining our environment in many ways… and something must be done. You should have already letters to the

government to help ban this awful, awful chemical

Surprise….

I have some DHMO with me today.

Does anyone want to see it??

Naming Covalent

Compounds

Differences between ionic and covalent

IONIC2 ions come

together!

Metal + Nonmetal

COVALENT

No ions!

Nonmetal + Nonmetal

Examples:

Na1+ + O2- CO2

Naming Ionic and Covalent Compounds

Key Point #3: When naming compounds, you must know which rules to use (ionic or covalent).

Ionic: Metal + Nonmetal Covalent: Nonmetal + Nonmetal

Yo Yo! Let’s break it down!

IONICMetal + Nonmetal

Writing Formulas:Kriss Kross chargesNaming:2nd element ends in

–ide, ignore subscripts

COVALENTNonmetal + NonmetalWriting Formulas:Prefixes = subscript

#sNaming:Use prefixes, 2nd

element ends in -ide

A compound made from Lithium and Oxygen

How do we know if it is ionic or covalent? Metals and non-metals make ionic compounds

Naming Ionic Compounds

Ionic Bond

Ion: Li Ion: O

Li O

Ionic Bond

Ion: Li Ion: O

Li+ O2-

Ionic Bond

Ion: Li Ion: O

Li+ O2-

Ionic Bond

Cation: Li Anion: O

Li2O

Naming Ionic Compounds

MgO

Naming Ionic Compounds

MgO

Magnesium Oxide

Naming Ionic Compounds

CaCl2

Naming Ionic Compounds

CaCl2

Calcium Chloride

Naming Ionic Compounds

Al2O3

Naming Ionic Compounds

Al2O3

Aluminum Oxide

Naming covalent compounds

No Kriss Krossing!

Naming Covalent Compounds

PCl3

How do we know if this is a covalent compound? Is it between a metal and a non-metal? NO!!! Then, it is not ionic!!!

Is it between a non-metal and a non-metal? YES!!! Then, it is covalent!

Naming Covalent Compounds

Rule 1: If the first element has more than one atom, give it a

prefix.

Naming Covalent Compounds1 – mono- 2 – di-

3 – tri- 4 – tetra-5 – penta- 6 – hexa-7 – hepta- 8 – octa-9 – nona- 10 – deca-

Naming Covalent Compounds

PCl3

Naming Covalent Compounds

PCl3

Phosphorous

Naming Covalent Compounds

Rule 2: The second element always gets a

prefix, uses the root of the word and ends in -ide.

Naming Covalent Compounds

PCl3

Phosphorous

Naming Covalent Compounds

PCl3

PhosphorousTrichloride

Naming Covalent Compounds

Rule 3: The “o” or “a” at the end of

the prefix is dropped if the

element begins in a vowel.

Naming Covalent Compounds

N2O

Naming Covalent Compounds

Rule 1: If the first element has more than one atom, give it a

prefix.

Naming Covalent Compounds

N2O

Dinitrogen

Naming Covalent Compounds

Rule 2: The second element always gets a

prefix, uses the root of the word and ends in -ide.

Naming Covalent Compounds

N2O

Dinitrogen Monooxide

Naming Covalent CompoundsRule 3: The “o”

or “a” at the end of the prefix is dropped if the element begins

in a vowel.

Naming Covalent Compounds

N2O

Dinitrogen Monooxide

Naming Covalent Compounds

N2O

Dinitrogen Monoxide

Practice Time!

EXAMPLESCCl4As2O

Whiteboards

SO

Sulfur Monoxide

NO2

Nitrogen Dioxide

N2O

Dinitrogen Monoxide

P2O5

Diphosphorous Pentoxide

PCl5

PhosphorousPentachloride

NF3

NitrogenTrifluoride

Independent Practice Time

Lucky you!

Write the names and formulas…First! Decide if it’s ionic or covalent!

Write names

1. Na2O2. CO2

3. GeBr4

4. Na2CO3

5. Mg3P2

6. K2S7. N2S3

Write formulas

1. Carbon monoxide2. Barium nitrate3. Xenon difluoride4. Carbon tetrachloride5. Sodium carbonate6. Lithium fluoride7. Nitrogen trifluoride

Exit Question

1. Write the formula for: Silicon dioxide Dihydrogen monoxide

2. Write the name for the following compounds:

CO2

NH3