Contextualization

Chemistry is a subject that surrounds us in our daily lives, from the air we breathe to the food we eat and the clothes we wear. One of the fundamental concepts in chemistry is the understanding of how atoms bond together to form molecules. Lewis diagrams, also known as Lewis structures or electron dot diagrams, are an essential tool in visualizing and understanding this process.

Lewis diagrams were first introduced by Gilbert N. Lewis in 1916 as a way to represent the valence electrons of an atom and how these electrons interact with other atoms in a molecule. They consist of the chemical symbol of the element, representing the nucleus and the inner electrons, surrounded by dots that represent the valence electrons. The arrangement of these dots around the symbol follows specific rules, which help predict the nature of the chemical bond.

Importance of Lewis Diagrams

Understanding Lewis diagrams is crucial in many areas of chemistry. They help predict the geometry of molecules, the polarity of bonds and molecules, and the reactivity of substances. These predictions are essential in fields such as drug design, environmental science, and materials science. For example, understanding the polarity of a molecule is crucial in understanding its solubility and its interactions with other molecules in biological systems.

Resources

• Khan Academy: Lewis structures
• Chem LibreTexts: Lewis Structures
• Crash Course Chemistry: Lewis Structures
• Chem4Kids: Lewis Diagrams

Practical Activity

Activity Title: "Building Molecules: A Journey into Lewis Diagrams"

Objective of the Project:

The main objective of this project is to provide a hands-on experience to students to understand, create, and analyze Lewis diagrams by constructing models of simple molecules and polyatomic ions. This project aims to enhance students' understanding of how atoms form bonds and the role of valence electrons in these interactions.

Detailed Description of the Project:

In this project, students will work in groups of 3 to 5 and will be divided into two teams: the "Molecule Builders" and the "Lewis Analysts." The Molecule Builders will construct models of simple molecules and polyatomic ions using modeling kits or any available materials. The Lewis Analysts will then create Lewis diagrams of the constructed models and analyze them for the understanding of the molecular structure and bonding.

Necessary Materials:

1. Modeling kits or any other materials to build molecular models (e.g., Styrofoam balls, toothpicks, plasticine)
2. Periodic Table
3. Notebook and pen for note-taking

Detailed Step-by-Step for Carrying Out the Activity:

Step 1: Introduction and Research (Approximately 5 hours)

• Each group should begin by conducting research on Lewis diagrams. They should use the resources provided and any other reliable sources they find.
• The students should discuss and share their findings within their group, making sure that everyone has a clear understanding of Lewis diagrams.

Step 2: Model Construction (Approximately 7 hours)

• The Molecule Builders will select five different simple molecules (e.g., water, carbon dioxide, methane) and two polyatomic ions (e.g., ammonium, sulfate) to construct models of.
• They will use the modeling kits or materials to build the models, ensuring that they accurately represent the structure of each molecule or ion.

Step 3: Lewis Diagram Creation and Analysis (Approximately 10 hours)

• The Molecule Builders will pass their models to the Lewis Analysts, who will create Lewis diagrams of each model. They should follow the rules of Lewis diagrams accurately.
• The Lewis Analysts will then analyze the diagrams and discuss within their group the implications of the structure and bonding in each molecule or ion.

Step 4: Report Writing (Approximately 5 hours)

• Each group will write a detailed report on their project, following the structure: Introduction, Development, Conclusions, and Used Bibliography.

  • In the Introduction, students should contextualize the theme, its relevance, and real-world application, as well as the objective of this project.
  • The Development section should detail the theory behind Lewis diagrams, explain the activity in detail, indicate the methodology used, and present and discuss the obtained results.
  • The Conclusion should revisit the project's main points, explicitly stating the learnings obtained and the conclusions drawn about the project.
  • The Used Bibliography should cite all the sources that were used to work on the project.

Project Deliverables and Their Connection to the Objective:

1. Physical Molecule Models: These models will demonstrate the student's ability to understand the structure of molecules and ions and their ability to create accurate representations of these structures.

2. Lewis Diagrams: The Lewis diagrams created by the students will show their understanding of how atoms bond to form molecules and ions and how to represent these bonds using Lewis diagrams.

3. Project Report: The final report should reflect the students' understanding of Lewis diagrams, their ability to work collaboratively, and their ability to communicate the results of their work in a clear and organized manner.

This project not only assesses the students' knowledge and understanding of Lewis diagrams but also their research skills, problem-solving skills, creativity, and ability to work in a team. It will require students to apply the concepts learned in class to a real-world scenario, enhancing their understanding and retention of these concepts. Finally, the project will also provide an opportunity for students to reflect on their learning process, making it a comprehensive and valuable educational experience.