UNIT 3 DAY 4

Covalent Bonds

Do Now/Catalyst (8 min)

Take out your notes packet from Unit 3. Answer the following questions on a separate sheet of paper.1. Write the chemical formula for the ionic

compound that will form and then draw the electron transfer diagrams

Li and O

Do Now/Catalyst: Check Answers (2 min)

1. Write the chemical formula for the ionic compound will form with the following elements and then draw the electron transfer diagrams

Li and O = Li2O

How are you doing?

Period 1 Period 5 Period 7 Period 2 Period 4 Period 6 Period 80

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7989

Unit 3 Day 1: Cations and Anions Class Av-erage Mastery

How are you doing?

Period 1 Period 5 Period 7 Period 2 Period 4 Period 6 Period 870

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Unit 3 Day 2: Types of Bonding Class Av-erage Mastery

Introduction (5 min)

Entrance Slip: Write your name and period at the top. If you did not do Day 2 or Day 3 Questions, do those nowAnswer the questions under Day 4.You may use your notes.SHOW:

Ion charges for K and O (1pt) Chemical formula (cross over charges)

(1pt) Complete Electron Transfer Diagram (2pt)

Announcements

Lab feesBehavior grade every two weeksACT tutoring Sat 9am-12pmOffice hours: Monday, Wednesday and Friday New homework policy – NO late work

acceptedBRING YOUR NOTES PACKET EVERYDAY!

Homework Due Exam Unit 3Friday 11/9 ODD Wednesday 11/14

ODDTuesday 11/13 EVEN

Thursday 11/15 EVEN

Objectives

SWBAT explain the formation of covalent bonds.

SWBAT draw Lewis Structures to represent the formation of covalent compounds.

REAL WORLD!!

Gasoline is made of C-H bonds…which are covalent bonds!!

Covalent Bonds

In Covalent Bonds, electrons are shared. Covalent bonds form between non-metals because of similarities in electronegativity.

To depict the formation of covalent bonds, we use Lewis structures.

Lewis Structures

In Lewis structures, we show a bond using line. Each bond represents two electrons. Bonds can be either single (one line), double (two lines), or triple three lines).

To show lone electrons (those that are not shared), we draw dots.

Steps for drawing a Lewis Structure

1. Write out the number of valence electrons for each atom in the compound.

2. Multiply this number by the number of atoms of that element in the compound.

3. Add up all the valence electrons.

Steps for drawing a Lewis Structure

4. Determine how many electrons would be needed for each atom in the compound to have an octet.

o Multiply the number of atoms by 8, except for H and He, which should be multiplied by two.

5. Compare the answer to Step 3 to the answer to Step 4. If the numbers don’t match, subtract, then divide your answer by two. This is the number of bonds you will need to draw.

Steps for drawing a Lewis Structure

6. Write the symbol of the least electronegative atom in the middle, and all other atoms around it. Draw one bond to each atom.

7. If you have bonds left over, draw more between the central atom and the other atoms.

8. When you’ve used all the bonds, draw dots around the other atoms until each has an octet. Remember to count each bond as two electrons.

Lewis Structure: CO2

Draw the Lewis structure for CO2:

PRACTICE TIME!!

Grab Whiteboard, an eraser, and a dry erase

marker

We Do: Whiteboard Practice Problems

Draw a Lewis structure for the following compound (copy into your notes):

SiO2

We Do: Whiteboard Practice Problems

Draw a Lewis structures for the following compound (copy into your notes):

CCl4

We Do: Whiteboard Practice Problems

Draw a Lewis structure for the following compound (copy into your notes):

H2O

We Do: Whiteboard Practice Problems

Draw a Lewis structure for the following compound:

HCN

We Do: Whiteboard Practice Problems

Draw a Lewis structure for the following compound:

HF

We Do: Whiteboard Practice Problems

Draw a Lewis structure for the following compound:

NH3

We Do: Whiteboard Practice Problems

Draw a Lewis structure for the following compound:

CH4

You Do: Independent Practice Problems

Answer the following book problems AND draw Lewis structures for each problem:P. 229 #7, 8P. 238 #11, 20P. 253 #31, 35

Closing

Essential Question:

How and why do electrons move between atoms when covalent bonds are formed?