Objectives (5 - 7 minutes)

1. Understanding the concept of sigma and pi bonds: The teacher must ensure that students understand what a sigma bond and a pi bond are, their differences, and how they contribute to the stability of organic molecules.

2. Identification of sigma and pi bonds in molecular structures: Students should be able to identify and draw sigma and pi bonds in molecular structures. This involves recognizing single, double, and triple bonds and the ability to correctly assign the type of bond to each bond in a structure.

3. Connection between the nature of sigma and pi bonds and chemical reactivity: Students should be able to relate the nature of sigma and pi bonds to the chemical reactivity of molecules. This includes understanding how the breaking of sigma and pi bonds during chemical reactions affects the overall reactivity of the molecule.

Secondary Objectives:

• Development of problem-solving skills: Through the practice of identifying and drawing sigma and pi bonds, students will have the opportunity to develop their problem-solving skills, critical thinking, and spatial skills.

• Stimulation of interest in organic chemistry: By better understanding the nature of organic bonds, students can develop a greater interest and appreciation for organic chemistry and its relevance to the world around them.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher should start the lesson by briefly reviewing the concepts of chemical bonds, specifically covalent bonds, which are essential for understanding sigma and pi bonds. Students should be reminded that covalent bonds involve the sharing of electrons between atoms and that the sum of sigma and pi bonds in a molecule is equal to the number of shared electron pairs between atoms.

2. Problem Situation: The teacher can then propose two problem situations to instigate students' curiosity and introduce the topic in a practical way. The first situation could be: "Why are some molecules more reactive than others?" and the second: "How does a molecule's structure affect its properties and chemical behavior?" These questions will serve as a starting point for the discussion on sigma and pi bonds and their relationship to chemical reactivity.

3. Contextualization: Next, the teacher should contextualize the importance of the topic with everyday examples. For example, it can be mentioned that understanding sigma and pi bonds is essential to understand why certain medications are effective, how chemical reactions occur in our bodies and in our food, and even how air and water pollution occurs and can be avoided.

4. Introduction to the Topic: After contextualization, the teacher should introduce the topic of sigma and pi bonds in an engaging way. They can share some curiosities, such as the discovery of sigma and pi bonds by Linus Pauling, which earned him the Nobel Prize in Chemistry in 1954. Another curiosity is that the theory of sigma and pi bonds is fundamental to the chemistry of life, as it is how carbon atoms bond to form most of the molecules found in living organisms.

5. Lesson Objectives: Finally, the teacher should present the lesson objectives, which include understanding the concept of sigma and pi bonds, identifying these bonds in molecular structures, and connecting the nature of these bonds to chemical reactivity. The teacher should emphasize that by the end of the lesson, students should be able to apply this knowledge to solve problems and questions related to organic chemistry.

Development (20 - 25 minutes)

1. Practical Activity - "Connecting Molecules": The teacher should divide the class into groups of 3 to 4 students. Each group will receive a set of colored cards, representing different atoms (e.g., carbon, hydrogen, oxygen, nitrogen) and colored rubber bands, representing sigma and pi bonds. The goal of the activity is to build different organic molecules, following valence bonding rules and using sigma and pi bonds correctly. The teacher can provide a quick reference guide with examples of molecules that students should try to replicate. This activity allows students to visualize and manipulate sigma and pi bonds, which can help solidify the concept in their minds.

   • Step by Step:
     1. Distribute the materials (cards and rubber bands) to each group.
     2. Explain the rules of the activity and show an example of how the materials should be used.
     3. Ask students to, in their groups, build different organic molecules using the provided materials.
     4. Circulate around the room, observing and assisting the groups as needed.
     5. At the end of the activity, ask each group to present one of the molecules they built and explain the sigma and pi bonds present in it.

2. Group Discussion: After the practical activity, the teacher should facilitate a group discussion about the students' observations and findings. This may include questions about which molecules were more challenging to build, which bonding rules they noticed, and how sigma and pi bonds influence the structure and reactivity of molecules. This discussion will allow students to apply what they have learned in a more abstract way and think critically about the topic.

3. Problem-Solving Activity - "Molecular Reactivity": For the second activity, the teacher should present students with a series of molecules and ask them to predict which one is more reactive based on their sigma and pi bonds. Students should justify their answers, explaining how the nature of sigma and pi bonds influences reactivity. This activity will allow students to apply what they have learned about sigma and pi bonds in a more complex and realistic way, directly relating it to chemical reactivity.

   • Step by Step:
     1. Present students with a series of molecules, such as methane, ethene, ethyne, and benzene.
     2. Ask students, in their groups, to discuss and predict which molecule is the most reactive and why, based on their sigma and pi bonds.
     3. Circulate around the room, observing and assisting the groups as needed.
     4. Ask each group to present their prediction and justification to the class.
     5. Discuss the answers with the class, reinforcing the connection between sigma and pi bonds and chemical reactivity.

4. Learning Check: At the end of the Development section, the teacher should quickly review the main concepts and check students' understanding through questions and answers. The teacher should also clarify any misunderstandings and provide constructive feedback to the students.

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes): The teacher should promote a group discussion with all students so they can share their experiences and conclusions from the activities. Each group will have a maximum of 2 minutes to present their solutions or conclusions. During these presentations, the teacher should encourage other students to ask questions and express their opinions. This group discussion will help consolidate students' understanding of the topic and identify any gaps in their knowledge.

   • Step by Step:
     1. Ask each group to share their solutions or conclusions from the activities in 2 minutes.
     2. Encourage other students to ask questions and express their opinions.
     3. Ask questions to check students' understanding and clarify any misunderstandings.
     4. Note any questions or concepts that need to be reviewed in the next lesson.

2. Connection with Theory (2 - 3 minutes): The teacher should then connect the activities carried out with the theory presented at the beginning of the lesson. This can be done by recalling the concepts of sigma and pi bonds and explaining how they apply to the molecular structures built by the students and the reactivity predictions they made. This step is crucial for students to realize the relevance of theory to practice and the real world.

   • Step by Step:
     1. Review the concepts of sigma and pi bonds and explain how they apply to the molecular structures built by the students.
     2. Explain how the nature of sigma and pi bonds influences the reactivity of molecules, using the students' predictions as examples.

3. Individual Reflection (2 - 3 minutes): Finally, the teacher should propose that students reflect individually on what they learned in the lesson. The teacher can ask questions like: "What was the most important concept you learned today?" and "What questions have not been answered yet?" Students will have a minute to think about their answers and then can share them if they wish. This final reflection will allow students to assess their own learning and identify any remaining doubts or difficulties.

   • Step by Step:
     1. Ask students to reflect individually on what they learned in the lesson.
     2. Ask guiding questions for reflection, such as "What was the most important concept you learned today?" and "What questions have not been answered yet?".
     3. Give students a minute to think about their answers.
     4. Encourage students to share their answers, if they wish.
     5. Note any doubts or difficulties that students mention to review in the next lesson.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher should start the Conclusion by summarizing the main contents covered during the lesson. This includes defining sigma and pi bonds, identifying these bonds in molecular structures, and the relationship between them and chemical reactivity. The teacher should reiterate the importance of understanding these concepts to deepen knowledge in organic chemistry.

   • Step by Step:
     1. Briefly review the definition of sigma and pi bonds.
     2. Recap how sigma and pi bonds are identified in molecular structures.
     3. Reinforce the connection between sigma and pi bonds and chemical reactivity.

2. Theory-Practice Connection (1 - 2 minutes): Next, the teacher should highlight how the lesson connected theory with practice. They should emphasize how the activities allowed students to apply the theoretical concepts of sigma and pi bonds in a practical and meaningful way. The teacher should stress that this connection is essential for a deep understanding of the topic.

   • Step by Step:
     1. Recap the practical activities carried out during the lesson.
     2. Explain how these activities allowed students to apply theoretical concepts in a practical way.
     3. Emphasize the importance of this connection between theory and practice for understanding the topic.

3. Additional Materials (1 minute): The teacher should suggest additional study materials for students who wish to deepen their understanding of sigma and pi bonds. These materials may include educational videos, organic chemistry websites, textbooks, and online exercises. The teacher should emphasize that reviewing these materials can be helpful to reinforce the concepts learned and prepare for future lessons.

   • Step by Step:
     1. Recommend additional study materials.
     2. Explain how these materials can help students deepen their understanding of the topic.

4. Everyday Applications (1 - 2 minutes): Finally, the teacher should highlight some practical applications of the concept of sigma and pi bonds in everyday life. This may include examples of how understanding these bonds is crucial for the production of medications, the analysis of environmental pollutants, and the understanding of many biological processes. The teacher should emphasize that organic chemistry has numerous real-world applications and that understanding sigma and pi bonds is a fundamental step to explore these applications.

   • Step by Step:
     1. Present the practical applications of the concept of sigma and pi bonds.
     2. Explain how understanding these applications can help students see the relevance of the topic to the real world.