Investigation 7A

Lewis Structures

2 Investigation 7A: Lewis Structures

Each water molecule contains one oxygen atom and two hydrogen atoms.

One central oxygen atom

One hydrogen atom on either side

Why can’t a water molecule be like this?

3 Investigation 7A: Lewis Structures

How many valence electrons does a hydrogen atom have?

How many valence electrons does an oxygen atom have?

How many electrons are available for bonding in hydrogen?

What about in oxygen?

How do bonds form?

4 Investigation 7A: Lewis Structures

How do bonds form?

5 Investigation 7A: Lewis Structures

How do bonds form?

6 Investigation 7A: Lewis Structures

Bonding patterns depend on the number of valence electrons.

Paired electrons do not make bonds.

Part 1: Introduction to Lewis dot diagrams

7 Investigation 7A: Lewis Structures

a. How many bonds should a hydrogen atom normally make?

b. How many bonds should a lithium atom normally make?

c. How many bonds should a carbon atom normally make?

d. How many bonds should a nitrogen atom normally make?

e. How many bonds should an oxygen atom normally make?

f. How many bonds should a helium atom normally make?

Part 1: Introduction to Lewis dot diagrams

8 Investigation 7A: Lewis Structures

How many holes does a red ball have?

How many holes does a black ball have?

How many holes does a blue ball have?

How many holes does a white ball have?

Part 2: Molecules and Lewis structures

Each group of 3 or 4 students should have 1 modeling kit

9 Investigation 7A: Lewis Structures

Can you guess which ball represents which type of atom?

Part 2: Molecules and Lewis structures

10 Investigation 7A: Lewis Structures

H2OChemical formula:

waterCommon name:

H O HStructural diagram: Lewis dot structure:

Part 2: Molecules and Lewis structures

11

Chemical formula ________________

Commonname _________________

Chemical formula ________________

Commonname _________________

Investigation 7A: Lewis Structures

Ethanol Oxygen

Build the following molecules: What type of bond is this?

Part 2: Molecules and Lewis structures

12

Chemical formula ________________

Commonname _________________

Chemical formula ________________

Commonname _________________

Investigation 7A: Lewis Structures

Formaldehyde Dichloroethylene

Build the following molecules:

Part 2: Molecules and Lewis structures

13

Chemical formula __________________

Commonname ___________________

Lewis structure

Chemical formula __________________

Commonname ___________________

Lewis structure

Investigation 7A: Lewis Structures

Build the following molecules:

Ethene Acetic acid

Part 3: Lewis structures from models

14

Chemical formula __________________

Commonname ___________________

Lewis structure

Chemical formula __________________

Commonname ___________________

Lewis structure

Investigation 7A: Lewis Structures

Build the following molecules:

Methylamine Ethanol

Part 3: Lewis structures from models

15 Investigation 7A: Lewis Structures

What is the chemical formula for a molecule made of the following atoms?

Part 4: Molecules with different structures

16 Investigation 7A: Lewis Structures

What is the chemical formula for a molecule made of the following atoms?

Create two different molecules, each with that same chemical formula. Each structure must use all available bonding sites on all atoms.

Be creative! Many diverse compounds can be created using these 8 atoms.

Part 4: Molecules with different structures

17 Investigation 7A: Lewis Structures

What is the chemical formula for a molecule made of the following atoms?

Create two different molecules, each with that same chemical formula. Each structure must use all available bonding sites on all atoms.

Create the Lewis structure for both of your molecules.

Part 4: Molecules with different structures