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!