11/3 what are lewis structures?
TRANSCRIPT
Launch: 11/3 Grab your binder and immediately take a seat!
1. Draw the correct Lewis symbols for the following atoms: i. hydrogen ii. neon iii. nitrogen
iv. bromine v. strontium
Schedule Monday (11/2): Covalent Bonds
Tuesday (11/3): Covalent Bonds
Wednesday (11/4): Covalent Bonds
Thursday (11/5): Covalent Bonds
Friday (11/6): Chemical Bonding Review
Monday (11/9): Chemical Bonding Review
Tuesday (11/10): Chemical Bonding Unit Exam!
Schedule We don’t have time to waste!
Follow our 6 class rules
If you have a question, ask! Ask your partner Ask me
What are Lewis structures?
Mr. Heffner 11/3/09
Review: Octet Rule Octet Rule:
all atoms want to have 8 valence electrons like the noble gases
Ne • • • •
• • • •
8 = 7 =
F • • • •
• • •
Review: Covalent Bonding To get 8, two nonmetals share electrons
F • • • •
• • • F
• • • •
• • •
7 = 7 =
Review: Covalent Bonding To get 8, two nonmetals share electrons
F • • • •
• • • F • • • • • • •
8 = 8 =
Covalent Bond
What are Lewis structures? Lewis structures are…
used to represent covalent bonds between atoms
Ne • • • • •
• • •
Lewis Symbol
Lewis structures are… used to represent covalent bonds between atoms
F • • • • • • -
What are Lewis structures?
Lewis Structure
F • • • •
• • Covalent Bond
2 electrons = dash
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 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 • •
Example
• - - - 8 dots
Example Draw the Lewis structure for HCl
Whiteboards Work in pairs
Trade-off marker every question
You have 60 seconds to draw the answer Show all three steps!
Lift board only when prompted
H2
Br2
SH2
CH4
Practice Questions Practice Questions worksheet
Exit Slip 1. In order to achieve a stable octet, two nonmetals
a. form ionic bonds by transferring electrons. b. form ionic bonds by sharing electrons.
c. form covalent bonds by sharing electrons. d. form metallic bonds by sharing electrons.
Exit Slip 2. See whiteboard.
Exit Slip 3. Which of the following correctly identifies the
Lewis structure for HF?
Exit Slip 4. Bubble in A
Then, draw the Lewis structure for HI
Exit Slip 5. Bubble in A
Then, draw the Lewis symbol for CBr4
Homework Finish Lewis symbol and ions worksheet