Objectives (5 - 7 minutes)

1. Understand the importance of the Periodic Table in Modern Chemistry:

   • Identify the role of the Periodic Table in the classification and organization of chemical elements.
   • Understand how the Periodic Table contributes to predicting properties of elements.

2. Appreciate the historical development of the Periodic Table:

   • Know the main scientists and their contributions to the creation and evolution of the Periodic Table.
   • Relate the historical context to the development of the Periodic Table.

3. Develop research and information analysis skills:

   • Use reliable sources to obtain information about the history of the Periodic Table.
   • Analyze and interpret the information obtained critically and reflectively.

Secondary Objectives:

• Stimulate active participation of students, promoting discussions and questioning on the subject.
• Foster students' curiosity and interest in Chemistry, highlighting the importance of the Periodic Table in the study of this science.

Introduction (10 - 15 minutes)

1. Review of Previous Content: The teacher should start the lesson by reviewing some basic concepts of Chemistry that are fundamental for understanding the lesson content. These may include the definition of chemical element, atom, atomic number, atomic mass, and how they are represented in the Periodic Table. This review can be done through a quick interactive quiz or group discussion.

2. Problem Situation: The teacher should then present two problem situations to the students in order to arouse their interest in the lesson topic. These may be:

   • "Why are chemical elements organized in the Periodic Table the way they are? How does this organization help us understand the properties of elements and predict new ones?"
   • "Who are the scientists behind the creation of the Periodic Table and how did they contribute to the development of Chemistry?"

3. Contextualization: The teacher should then contextualize the importance of the subject, explaining how the Periodic Table is crucial for Modern Chemistry and for various practical applications, from industry to medicine. Additionally, the relevance of understanding the history of the Periodic Table for appreciating scientific work and the process of discovery can be highlighted.

4. Introduction to the Topic: To capture students' attention, the teacher can share some curious or interesting stories related to the lesson topic. These may include:

   • "Did you know that the first version of the Periodic Table, created by Dmitri Mendeleev in 1869, had empty spaces that he predicted would be filled by elements that had not yet been discovered? And he was right! Germanium, gallium, and scandium were discovered shortly after and filled those spaces."
   • "Do you know the story of how the Periodic Table was created? It was the result of decades of work by various scientists, and it was a major breakthrough in understanding Chemistry. But the story is not as simple as it seems! Let's find out more about it today."

Development (20 - 25 minutes)

1. Activity "Periodic Table Chronology" (10 - 12 minutes)

   • Divide the class into groups of 4 or 5 students.
   • Provide each group with a large sheet of sulfite paper and colored markers.
   • Each group should draw a timeline of the Periodic Table, including the main milestones of its history, such as the discovery of the first elements, the contributions of the main scientists, changes in the Table's structure, etc.
   • The teacher should provide the students with a list of important events to help them in the activity, but students should also be encouraged to do their own research.
   • After completing the timelines, each group should present theirs to the class, explaining the events they included and why they considered them important.
   • This activity allows students to visualize the evolution of the Periodic Table, relating it to the historical context and the contributions of scientists. Additionally, it promotes collaboration and discussion among group members.

2. Activity "Scientific Treasure Hunt" (10 - 12 minutes)

   • Still in groups, students should receive a list of names of scientists who contributed to the development of the Periodic Table and a list of facts or discoveries related to these scientists.
   • The challenge is for students to find, on the internet or in textbooks, the information corresponding to each scientist and fact.
   • Each group should write down the information found on a poster and, at the end of the activity, present their results to the class.
   • The teacher should guide students to use reliable sources and to critically evaluate the information found.
   • This activity allows students to deepen their knowledge about the scientists who contributed to the Periodic Table, as well as develop research and information analysis skills.

3. Activity "Periodic Table Game" (optional, if time allows) (5 - 10 minutes)

   • This activity can be done as a fun closure of the lesson to review the concepts learned.
   • The teacher should prepare cards in advance with information about different elements of the Periodic Table (atomic number, symbol, atomic mass, properties, etc.).
   • In groups, students should play a memory game, trying to find pairs of cards with information corresponding to the same element.
   • At the end of the game, the group that found the most pairs of cards is the winner.
   • This activity not only promotes the review of learned concepts but also develops students' memory and teamwork skills.

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes)

   • The teacher should start a group discussion, where each team shares their conclusions and solutions to the activities carried out.
   • Each group will have a maximum of 3 minutes to present their results.
   • During the presentations, the teacher should encourage other groups to ask questions and make comments, thus promoting an environment of exchange and mutual learning.

2. Connection with Theory (2 - 3 minutes)

   • After the presentations, the teacher should make the connection between the activities carried out and the theory presented at the beginning of the lesson.
   • He should highlight how the activities helped students understand the importance of the Periodic Table in Modern Chemistry and appreciate its historical development.
   • He can also emphasize how research and information analysis skills were developed during the activities.

3. Individual Reflection (2 - 3 minutes)

   • To conclude, the teacher should propose that students reflect individually on what they learned in the lesson.
   • He can ask questions like:
     1. "What was the most important concept you learned today?"
     2. "What questions have not been answered yet?"
   • Students should write down their answers, which can serve as a starting point for the next lesson or for further individual study.

4. Feedback (optional)

   • If time allows, the teacher can ask students to give feedback on the lesson, what they liked, what they didn't like, what could be improved, etc.
   • This feedback can be used to enhance future lessons and to show students that their opinions and suggestions are valued.

This Return moment is essential to consolidate learning, allowing students to reflect on what they have learned, make connections with the real world and theory, and identify possible gaps in their understanding. Additionally, it promotes self-assessment and metacognition, valuable skills for autonomous learning.

Conclusion (5 - 7 minutes)

1. Summary and Recapitulation (2 - 3 minutes)

   • The teacher should start the Conclusion by reaffirming the main points discussed in the lesson, summarizing the history of the Periodic Table and highlighting the role of the main scientists who contributed to its creation and evolution.
   • He should emphasize the importance of the Periodic Table in Modern Chemistry and how it allows us to predict the properties of elements.
   • The teacher should also recall the activities carried out, reminding of the main insights and conclusions obtained by the students.

2. Connection between Theory, Practice, and Applications (1 minute)

   • Next, the teacher should explain how the lesson connected theory (the history of the Periodic Table and its importance in Modern Chemistry) with practice (research and information analysis activities) and applications (the possibility of predicting the properties of elements based on the organization of the Periodic Table).
   • He should highlight how the knowledge acquired in this lesson can be applied in real situations, such as solving chemical problems or understanding news and scientific articles that mention the Periodic Table.

3. Extra Materials (1 - 2 minutes)

   • The teacher should then suggest additional materials for students who wish to deepen their knowledge on the subject. These may include books, documentaries, websites, and interactive apps about the Periodic Table and the history of Chemistry.
   • He can also recommend exercises and online activities that allow students to apply the learned concepts in a practical way.

4. Relevance of the Subject (1 minute)

   • Finally, the teacher should highlight the importance of the lesson subject for students' daily lives, explaining how the Periodic Table is used in various areas, from industry to medicine.
   • He can emphasize that understanding the history of the Periodic Table not only enriches students' knowledge of Chemistry but also helps them appreciate scientific work and the process of discovery, thus developing a curious and respectful attitude towards science.

This Conclusion serves to consolidate learning, stimulate students' curiosity and interest in the subject, and show the relevance of it to their lives and the world around them. Additionally, by suggesting extra materials and deepening activities, it encourages autonomous study and the continuity of learning outside the classroom.