2 9 chemical bonding benchmark review part ii

Launch: 2/8   Grab your binder and immediately take a seat!

  Place launch paper and yesterday’s practice questions on your desk.

  Friday’s Quiz Data:

  Today’s Objectives: I can draw a Lewis structure.

90%!

Launch 2/8

1. Look around the classroom and make a list of all the new things you can see.

Launch 2/8 2.  Which of the following is true about the Kinetic

Molecular Theory? a) It can be used to measure the speed of molecules. b) It states that gas molecules more slower at high

temperatures. c) It states that the motion of a gas particle is fast

and random d) All of the above.

Launch 2/8 3.  Pressure is created by

a) the diffusion of two or more gases. b) the random motion of molecules and their

collisions with a surface. c)  the phase change that occurs at 0°C. d) the force of a solid exerted on the interior of a gas.

Announcements   Quiz scores handed out at the end of class

  New items in the classroom   Positive consequences   Negative consequences   Word wall

  Data wall   Shout Outs!

  Change in schedule!   Surprise benchmark

February Calendar

Exam!

Quiz!

Quiz!

Today Benchmark

Opening   Today’s Objective: I can classify a chemical bond as

either ionic, covalent, or metallic.

Chemical Bonding Review: Part II Mr. Heffner

2//09

  Lewis structures are…   pictures of covalent molecules

F •  •  •  •  •  •  -

What are Lewis structures?

Lewis Structure

F •  •  •  • 

•  •  Covalent Bond

2 electrons = dash

Example #1 Draw the Lewis symbol for carbon.

  Step 1: Place element’s symbol in center

C

Example #1 Draw the Lewis symbol for carbon.

  Step 2: # of valence electrons?

Example #1 Draw the Lewis symbol for carbon.

  Step 2: # of valence electrons?

“The Trick”: Group # Drop the 1!

group # = 14 # valence electrons = 4

Example #1 Draw the Lewis symbol for carbon.

  Step 3: Place electrons around symbol   One on each of the 4 sides   No doubling up!

C •  •  • 

• 

What is a Lewis structure?   There is a 3-step process for creating Lewis

structures: 1.  Draw Lewis symbol for each atom and count dots 2.  Arrange atoms so they all have a full octet

  If more than 2 atoms, place first atom in center

3.  Count dots and convert shared pairs to bonds

Example Draw the Lewis structure for Cl2

  Step 1: Draw Lewis symbol for each atom and count dots

Cl •  •  •  • 

•  •  •  Cl

•  •  •  • 

•  •  •  14 dots

Example Draw the Lewis structure for Cl2

  Step 2: Arrange atoms so they have a full octet

Cl •  •  •  •  •  •  •  Cl

•  •  •  • 

•  •  •  8 = 8 =

Example Draw the Lewis symbol for Cl2

  Step 3: Count dots and convert shared pairs to dashes

Cl •  •  •  •  •  •  •  Cl

•  •  •  • 

•  •  •  14 dots

- Covalent Bond

2 electrons = dash

Example Draw the Lewis structure for NH3

  Step 1: Draw Lewis symbol for each atom and count dots

N •  •  • 

•  •  8 dots H

•  H •  H

• 

Draw the Lewis structure for NH3

  Step 2: Arrange atoms so they have a full octet   If more than two atoms, place first atom in center

N •  • 

•  •  •  H •  H • 

Example

H • 

8 = 2 =

H is an exception to the octet rule

H H

Draw the Lewis symbol for Cl2

  Step 3: Count dots and convert shared pairs to dashes

N •  • 

•  •  •  H •  • 

Example

•  - - - 8 dots

Example Draw the Lewis structure for CH4

Practice Questions   Review worksheet

Exit Slip 1.  In covalent bonding,

a.  valence electrons are exchanged. b.  only metals interact with other metals.

c.  valence electrons are shared d.  atoms become less stable due to the octet rule.

Exit Slip 2.  Covalent bonds form between which two types of

elements? a.  metals and metals b.  metals and nonmetals c.  nonmetals and nonmetals

d.  none of the above

Exit Slip 3.  Ionic bonds form between which two types of

elements? a.  alkali and alkaline earth metals b.  halogens and other halogens c.  metals and nonmetals

d.  nonmetals and other nonmetals

Exit Slip 4.  What type of compound is H2SO4?

a.  metallic b.  covalent

c.  ionic d.  none of the above

Exit Slip 5.  Which of the following is an example of an ionic

compound? a.  AlCl3 b.  CCl4 c.  O2

d.  Zn2+

Homework   Finish the review worksheet

  Study hard for Tuesday’s exam!