Objectives (5 - 7 minutes)

1. Understand the concept of ionic bonding and its main characteristics, such as the formation of ions and the attraction between opposite charges.
2. Understand the concept of covalent bonding and its main characteristics, such as electron sharing and the formation of molecules.
3. Differentiate between ionic and covalent bonds, highlighting the main differences in terms of properties and structures.

Secondary objectives:

• Apply the knowledge acquired in identifying and classifying different chemical substances according to the predominant type of bond.
• Develop critical thinking and problem-solving skills by applying the concept of chemical bonding in real-world contexts, such as in explaining natural phenomena or predicting chemical behavior.

Introduction (10 - 12 minutes)

1. Review of Previous Content: The teacher should start the class by briefly reviewing the concepts of atoms, ions, and molecules, emphasizing the structure of atoms and the distribution of electrons in their layers. This review is crucial for students to understand the process of forming ionic and covalent bonds. (3 - 4 minutes)

2. Problem Situations: The teacher should then present two problem situations to arouse the students' interest and contextualize the theme.

   • The first situation may involve the formation of an ionic compound, such as table salt (NaCl), and the question "Why does table salt dissolve easily in water?"

   • The second situation may involve the formation of a covalent compound, such as water (H2O), and the question "Why is water a liquid at room temperature, while salt is a solid?" (4 - 5 minutes)

3. Contextualization: The teacher should then contextualize the importance of the topic, explaining how ionic and covalent bonds are fundamental to the formation and stability of all substances around us. You can mention everyday examples, such as the importance of covalent bonds in the formation of plastic materials and the importance of ionic bonds in the formation of minerals. In addition, it can be discussed how the understanding of these bonds is crucial in many areas, such as medicine, materials engineering, and pharmacology. (2 - 3 minutes)

4. Introduction to the Topic: Finally, the teacher should introduce the topic of the lesson, presenting the concept of chemical bonding and explaining that ionic and covalent bonds are two main ways in which atoms come together to form substances. It can be mentioned that, although the concepts of ions and molecules have been studied in previous classes, today's class will deepen these concepts and show how they relate to chemical bonds. (2 - 3 minutes)

Development (20 - 25 minutes)

1. Presentation of the Theory (10 - 12 minutes)

   1.1. Definition of Chemical Bonding: The teacher should begin by explaining that the chemical bond is the force that holds atoms together in a compound. It can be mentioned that, although atoms tend to have a stable electronic configuration with eight electrons in the valence shell (octet rule), it is not always possible to achieve this configuration alone, which leads to the formation of chemical bonds. (2 - 3 minutes)

   1.2. Ionic Bonding: The teacher should then explain that ionic bonding occurs when there is a complete transfer of electrons from one atom to another. A visual model of the atoms can be used, showing how the atom that loses electrons becomes a positive ion (cation) and the atom that gains electrons becomes a negative ion (anion). It should be emphasized that ions of opposite charges attract each other strongly, holding the atoms together in the compound. (3 - 4 minutes)

   1.3. Covalent Bonding: The teacher should then explain that covalent bonding occurs when atoms share electrons in order to achieve the stable electronic configuration of eight electrons in the valence shell. A visual model can again be used, showing how electrons are shared between atoms. It should be emphasized that, in covalent bonding, there is no complete transfer of electrons, but rather a sharing. (3 - 4 minutes)

   1.4. Differences between Ionic and Covalent Bonding: Finally, the teacher should summarize the main differences between ionic and covalent bonds. It can be mentioned that, in ionic bonding, there is a complete transfer of electrons, resulting in the formation of ions, while in covalent bonding, electrons are shared. It can also be mentioned that ionic bonds tend to occur between metals and non-metals, while covalent bonds tend to occur between non-metals. (2 - 3 minutes)

2. Examples and Applications (5 - 7 minutes)

   2.1. The teacher should then present some examples of substances that are formed by ionic bonds and others by covalent bonds. Molecular models can be used to illustrate these examples. For example, table salt (NaCl) is an example of a substance formed by ionic bonding, while water (H2O) is an example of a substance formed by covalent bonding. (2 - 3 minutes)

   2.2. The teacher should then discuss the properties of these substances that are consequences of the ionic and covalent bonds. For example, due to the nature of ionic bonds, ionic compounds tend to have high melting and boiling points, and to be good conductors of electricity when in aqueous solution or melted. On the other hand, due to the nature of covalent bonds, covalent compounds tend to have lower melting and boiling points, and to be poor conductors of electricity. (2 - 3 minutes)

   2.3. Finally, the teacher should discuss some real applications of these concepts. For example, it can be mentioned that the knowledge about chemical bonds is crucial in the pharmaceutical industry, as it allows understanding how drugs interact with the body. It can also be mentioned that the knowledge about chemical bonds is fundamental in materials engineering, as it allows designing materials with specific properties. (1 - 2 minutes)

3. Practical Modeling Activity (5 - 6 minutes)

   3.1. The teacher should then propose a practical modeling activity, in which students will have to build models of simple substances (such as table salt and water) using colored marbles to represent the different atoms and toothpicks to represent the bonds. The purpose of this activity is to allow students to visualize the ionic and covalent bonds and understand how they affect the structure and properties of substances. (3 - 4 minutes)

   3.2. Students should be encouraged to discuss among themselves and with the teacher during the activity, clarifying doubts and sharing observations. The teacher should go around the room, guiding students and answering questions as needed. (2 - 3 minutes)

Return (8 - 10 minutes)

1. Group Discussion (3 - 4 minutes) 1.1. The teacher should start a group discussion with all students so that they can share the solutions or conclusions found during the practical activity. 1.2. Each group should have the opportunity to present the model they built and explain how the ionic and covalent bonds were represented and how this affects the properties of the modeled substance. 1.3. During the presentations, the teacher should ask questions to stimulate critical thinking and ensure that all students understand the concepts presented.

2. Connection with the Theory (2 - 3 minutes) 2.1. After the presentations, the teacher should return to the theoretical concepts presented and make the connection with the practical activities performed. 2.2. The teacher can reinforce the idea that the structure of substances and their properties are directly linked to the type of predominant bond. 2.3. The teacher should also reinforce the importance of understanding ionic and covalent bonds for chemistry and for various areas of science and technology.

3. Individual Reflection (3 - 4 minutes) 3.1. Finally, the teacher should propose that students individually reflect on what they learned during the class. 3.2. The teacher can ask questions such as: "What was the most important concept you learned today?", "What questions have not yet been answered?" and "How can you apply what you learned today in everyday situations or in other disciplines?" 3.3. Students should have a minute to think about the answers to these questions. They can write down their reflections, if they wish. 3.4. After the minute of reflection, the teacher can ask some students to share their answers. The teacher should listen carefully and provide feedback, clarifying doubts and making connections with the next class.

This Return is crucial to consolidate learning, allow students to express their doubts and reflections, and for the teacher to evaluate the effectiveness of the class and plan the next steps of teaching. In addition, by promoting group discussion and individual reflection, the Return contributes to the Development of students' communication and critical thinking skills.

Conclusion (5 - 7 minutes)

1. Summary of Content (2 - 3 minutes) 1.1. The teacher should begin the Conclusion by reiterating the fundamental concepts of the class. The definition of chemical bonding and the main characteristics of ionic and covalent bonds should be summarized. 1.2. The teacher should recall the differences between these two types of bonds, highlighting the complete transfer of electrons in ionic bonding and the sharing of electrons in covalent bonding. 1.3. The teacher should reinforce that the formation of these bonds is crucial for the stability and the properties of substances.

2. Connection between Theory, Practice, and Applications (1 - 2 minutes) 2.1. The teacher should then highlight how the class connected theory, practice, and applications. It should be mentioned how the construction of models during the practical activity helped to visualize the ionic and covalent bonds and to understand how they affect the structure and properties of substances. 2.2. The teacher should reinforce the practical applications of these concepts, such as in the pharmaceutical industry and in materials engineering, and how they help to explain everyday phenomena, such as the dissolution of salt in water and the properties of water.

3. Extra Materials (1 - 2 minutes) 3.1. The teacher should suggest extra materials for students who wish to deepen their knowledge on the topic. These materials may include explanatory videos, interactive chemistry websites, textbooks, and additional exercises. 3.2. The teacher can also suggest that students perform simple experiments at home, such as dissolving different substances in water, to observe in a practical way the differences between ionic and covalent bonds.

4. Importance of the Topic (1 - 2 minutes) 4.1. Finally, the teacher should emphasize the importance of the concepts learned for the students' everyday life. It should be mentioned that understanding chemical bonds is fundamental to understanding the structure and behavior of the substances around us. 4.2. The teacher should also emphasize that the understanding of these concepts is not only relevant for chemistry, but also for many other areas of science and technology. It should be mentioned that the ability to understand and manipulate chemical bonds is crucial for the Development of new materials, medicines, and technologies.