Objectives (5 - 7 minutes)

1. Understand the definition and structure of cyclic hydrocarbons, focusing on aromatic and aliphatic compounds.

2. Differentiate cyclic hydrocarbons from acyclic hydrocarbons, identifying the particularities of each.

3. Develop skills to name and classify cyclic hydrocarbons using the official IUPAC nomenclature.

Secondary Objectives:

• Stimulate critical thinking and problem-solving skills by performing practical exercises to identify and name cyclic hydrocarbons.

• Foster teamwork skills by proposing collaborative learning activities, such as small group discussions and problem-solving together.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher starts the lesson by reviewing the concepts of hydrocarbons and their classifications, with an emphasis on acyclic hydrocarbons. It is important for students to have a solid understanding of these topics in order to advance to the study of cyclic hydrocarbons. The teacher can ask students questions to check understanding and clarify any possible doubts.

2. Presentation of Problem Situations: The teacher proposes two problem situations to arouse students' interest. The first situation could be: 'Imagine you are a scientist and need to identify the organic compound present in a certain substance. How would you do that?' The second situation could be: 'If you were chemists working in the pharmaceutical industry, how could you use knowledge about cyclic hydrocarbons in the development of new drugs?'

3. Contextualization: The teacher contextualizes the importance of studying cyclic hydrocarbons, explaining that these compounds are present in various substances in our daily lives, such as in medications, dyes, flavorings, among others. Additionally, they are of great importance in the chemical and pharmaceutical industries.

4. Gaining Attention: To capture students' attention, the teacher can share curiosities about cyclic hydrocarbons. For example, they can mention that the first aromatic compound to be synthesized in the laboratory was benzene, in 1825, by Michael Faraday. Another curiosity is that, despite benzene being highly flammable, it is used in the production of many plastics and rubbers that do not burn easily.

5. Introduction to the Topic: The teacher then introduces the topic of the lesson, explaining that cyclic hydrocarbons are compounds that have one or more closed chains of carbon atoms. They can show images of some examples of cyclic hydrocarbons, such as benzene, toluene, and naphthalene, and explain that, despite resembling acyclic hydrocarbons, they have different properties and uses.

By the end of this stage, students should be prepared and motivated for a more in-depth study of the topic.

Development (20 - 25 minutes)

1. Research and Presentation Activity (10 - 15 minutes)

   • Group Formation: The teacher divides the class into groups of up to five students and assigns each group a different cyclic hydrocarbon for research. The hydrocarbons may include benzene, toluene, naphthalene, anthracene, and phenanthrene.
   • Research: Each group should research the assigned cyclic hydrocarbon, including its structure, physical and chemical properties, occurrence in nature, and main industrial and commercial applications.
   • Presentation Preparation: Based on the research, the groups should prepare a brief presentation to share the information with the class. The presentation should include a three-dimensional model of the hydrocarbon's structure, if possible.
   • Presentation: Each group presents their findings to the class. The teacher should encourage participation from all students by asking questions and stimulating discussion.

2. Cyclic Hydrocarbons Nomenclature Game (5 - 10 minutes)

   • Preparation: The teacher prepares cards with different structural representations of cyclic hydrocarbons. Each card should be associated with an official IUPAC name.
   • Game: The groups receive a set of cards and must correctly match the structures with the names. The group that correctly matches all the cards first, or the highest number of cards in a certain time, wins the game.

3. Guided Discussion (5 - 10 minutes)

   • The teacher leads a guided discussion with the class, reviewing the main concepts and clarifying any doubts. The teacher can use questions like: 'What are the main differences between cyclic and acyclic hydrocarbons?' and 'What are the advantages and disadvantages of using cyclic hydrocarbons in industrial applications?' to stimulate students' reflection and critical thinking.
   • The teacher can also ask students to reflect on how the knowledge acquired in the lesson can be applied in everyday situations or in their future careers.

These activities provide students with the opportunity to explore the topic in more depth, developing their research, presentation, collaboration, and critical thinking skills. Additionally, the use of playful activities, such as the nomenclature game, makes learning more fun and engaging.

Return (5 - 7 minutes)

1. Group Discussion (2 - 3 minutes): The teacher should gather all students in a circle and promote a group discussion. Each group will have a minute to share their main findings and conclusions from the research and presentation activity. The teacher should encourage students to ask questions and make comments about the presentations of other groups, thus promoting collaborative learning.

2. Connection with Theory (1 - 2 minutes): The teacher should take advantage of the group discussion to make the connection between the practical activity and the theory. For example, if one group presented on benzene and another on toluene, the teacher can ask students how these two hydrocarbons are related and what their main differences are. This allows students to see the practical application of the theoretical concepts discussed in the lesson.

3. Individual Reflection (1 - 2 minutes): To conclude the lesson, the teacher should propose that students reflect for a minute on the following questions:

   • What was the most important concept learned today?
   • What questions have not been answered yet?
   • How can you apply what you learned today in your daily life or future career?

4. Sharing Reflections (1 minute): The teacher can ask some students to share their answers with the class. This not only helps consolidate learning but also provides the teacher with valuable feedback on what students have learned and which areas may need more attention in future lessons.

5. Closing: The teacher ends the lesson by reinforcing key concepts and giving a brief review of what was learned. They should also remind students about any homework or additional reading assigned and address any final questions students may have.

Conclusion (8 - 10 minutes)

1. Recapitulation (2 - 3 minutes): The teacher should start the Conclusion by recapping the main points discussed during the lesson. They should review the definition of cyclic hydrocarbons, the differences between these and acyclic hydrocarbons, and the official IUPAC nomenclature for these compounds. The teacher can do this through a brief slide presentation or simply by reiterating the most important concepts verbally.

2. Connecting Theory with Practice (2 - 3 minutes): Next, the teacher should explain how the lesson connected theory with practice. They should emphasize how the research and presentation activities allowed students to apply theoretical knowledge in practice, and how the nomenclature game helped consolidate students' understanding of cyclic hydrocarbons' nomenclature. The teacher can also mention examples of everyday situations or industry where knowledge about cyclic hydrocarbons can be useful, reinforcing the relevance of the topic.

3. Supplementary Materials (1 - 2 minutes): The teacher should then suggest supplementary materials for students who wish to deepen their understanding of the topic. This may include additional readings, educational videos, chemistry websites, or chemistry apps that allow students to explore the structure and properties of cyclic hydrocarbons interactively. The teacher can provide a list of these resources on the school's online learning platform or send them via email to students.

4. Importance of the Topic (2 - 3 minutes): To conclude the lesson, the teacher should reinforce the importance of the topic for students' daily lives and future careers. They should explain that even if students do not plan to pursue careers in chemistry, knowledge about cyclic hydrocarbons can be useful in various areas, such as understanding how medications act in the body, analyzing environmental pollutants, or even in the kitchen, by understanding how aromas and flavors are created. The teacher can also mention that the ability to understand and handle complex compounds, such as cyclic hydrocarbons, is a valuable skill that can be applied in many other contexts, not just in chemistry.

5. Closing: The teacher ends the lesson by thanking students for their participation, encouraging them to continue exploring the topic, and addressing any remaining questions. They should also remind students about homework, if any, and about the topic of the next lesson.