Lesson plan of Chemical Bonds: Metallic

Objectives (5-7 minutes)

1. Understand the concept of metallic bonding: Students should be able to understand what a metallic bond is, how it occurs, and what its main characteristics are. This includes understanding that the metallic bond involves the donation of valence electrons from an atom's valence shell to a "sea" of delocalized electrons.

2. Identify practical examples of metallic bonding: Students should be able to recognize examples of metallic bonding in their everyday lives and in industrial applications. This may include identifying pure metals, metal alloys, and substances that conduct electricity due to the presence of metallic bonds.

3. Distinguish metallic bonding from other chemical bonds: Students should be able to distinguish metallic bonding from other types of chemical bonds, such as ionic and covalent bonds. This can be done by comparing the characteristics and properties of each type of bond.

Secondary objectives:

• Promote critical thinking skills: Throughout the lesson, students should be encouraged to think critically about the concept of metallic bonding and how it applies to different situations. This can be done through group discussions and problem-solving exercises.

• Stimulate curiosity and interest in Chemistry: Through the presentation of practical examples and real-world applications, the lesson should pique students' interest in the study of Chemistry and show how it applies to their everyday lives.

Introduction (10-15 minutes)

1. Review of previous concepts:

   • The teacher should begin by reviewing the characteristics of metals, such as luster, electrical and thermal conductivity, and malleability. This will help students understand why metals have these properties, which are directly related to metallic bonding.
   • In addition, the concept of electron shells and electron configuration should be revisited, as it is essential for understanding how metallic bonding occurs.

2. Problem situations:

   • The teacher can propose two problem situations to pique students' curiosity. For example, ask why metals are good conductors of electricity and heat, and why they are malleable, while other materials, such as non-metals, do not have these properties on a large scale.
   • Another question could be: how are metals able to form alloys, such as steel, which can be harder and stronger than pure iron?

3. Contextualization:

   • The teacher should explain that metallic bonding is responsible for many of the properties and behaviors of the metals we encounter in our daily lives. For example, the electrical conductivity of copper wires, the malleability of gold for making jewelry, among others.
   • In addition, some industrial applications can be mentioned, such as the manufacture of metal alloys for the automotive, aerospace, and construction industries, and the use of metals in electronics and power generation.

4. Introduction to the topic:

   • The teacher should introduce the topic of metallic bonding, explaining that it is the force that holds the atoms of a metal together and is responsible for many of the unique properties of metals.
   • Curiosities can be used to grab students' attention, such as the fact that the metallic bond is so strong that it is able to hold the atoms of a metal together even when they are subjected to strong pressures or high temperatures.
   • In addition, it can be mentioned that metallic bonding is what allows metals to be recycled, since the metal atoms can be easily rearranged without the substance losing its metallic properties.

Development (20-25 minutes)

1. Practical activity: "Modeling Metallic Bonding"

   • The teacher should divide the class into groups of no more than five students and provide each group with a quantity of modeling clay balls of different colors and toothpicks.
   • Each clay ball of a different color represents an atom of a metallic element, and the toothpicks represent the valence electrons of these atoms.
   • Students should be instructed to model how metallic bonding occurs, that is, how the metal atoms donate their valence electrons to a "sea" of delocalized electrons, which move freely in the metal.
   • After the modeling, students should be asked about what they observed. It is expected that they will notice that the valence electrons are no longer "trapped" to a specific atom, but free to move between the metal atoms.
   • This activity helps to consolidate the concept of metallic bonding and the difference between "bound" valence electrons and free valence electrons.

2. Research and presentation activity: "Metallic Bonds in Practice"

   • The teacher should guide students to research practical examples of metallic bonding, that is, how metallic bonding manifests in objects and materials that they encounter in their daily lives.
   • Each group should choose an example and prepare a short presentation to share with the class. Some examples may include: why copper wires are used to conduct electricity, why metals are good conductors of heat, why metals are malleable and ductile, and why metal alloys have different properties from pure metals.
   • During the presentations, the other groups should ask questions to stimulate discussion and understanding of the concept of metallic bonding.

3. Problem-solving activity: "Metal Alloys and their Properties"

   • The teacher should propose a problem for the students to solve in groups. For example: "A company needs to produce a material that is lightweight, strong, and conducts electricity. What type of material should they use and why?"
   • Students should use the knowledge acquired about metallic bonding to solve the problem. They should identify that the company needs a metallic alloy, since metal alloys have properties that are a combination of the properties of the metals that compose them. In addition, they should identify which properties of metallic bonding are relevant to each company requirement.
   • After solving the problem, the groups should present their solutions to the class. The teacher should guide the discussion to ensure that students understand how metallic bonding manifests in the properties of materials.

Feedback (8-10 minutes)

1. Group discussion (3-4 minutes):

   • The teacher should gather all students and promote a group discussion about the solutions or conclusions found by each group.
   • Each group should have a maximum time of 3 minutes to share their findings. During the presentations, the teacher should encourage the other students to ask questions and make comments, promoting a collaborative learning environment.
   • This discussion allows students to see different perspectives on the same problem and learn from the ideas and experiences of their classmates.

2. Connection with the 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 class.
   • The teacher can revisit the key concepts of metallic bonding and explain how they were applied during the activities.
   • In addition, the teacher should highlight the skills and competencies developed by students during the lesson, such as the ability to solve problems, work in groups, and apply theoretical knowledge to practical situations.

3. Individual reflection (1-2 minutes):

   • The teacher should propose that students do a brief individual reflection on what they learned in the lesson.
   • To do so, the teacher can ask questions such as: "What was the most important concept you learned today?" and "What questions have not yet been answered?".
   • Students should have a minute to think about these questions. The goal of this reflection is for students to consolidate what they have learned and identify any doubts or difficulties they may have.

4. Feedback and clarification of doubts (2-3 minutes):

   • Finally, the teacher should open up space for students to share their reflections, questions, and doubts.
   • The teacher should answer the questions and clarify the students' doubts, ensuring that everyone has understood the lesson content.
   • In addition, the teacher should take advantage of this moment to give general feedback on the lesson, highlighting the positive points and indicating areas that need improvement.

Conclusion (5-7 minutes)

1. Summary and Recapitulation:

   • The teacher should recall the main points discussed during the lesson, recapitulating the concept of metallic bonding, its characteristics, and how it differs from ionic and covalent bonds.
   • The main properties of metals that result from metallic bonding, such as electrical and thermal conductivity, malleability, and ductility, should also be reinforced.
   • It is important for the teacher to verify that all students have understood these fundamental concepts, clarifying any remaining doubts.

2. Theory-Practice Connection:

   • The teacher should highlight how the lesson connected the theory of metallic bonding to the practices of modeling, research, and problem-solving.
   • It should be emphasized how the practical activities helped to solidify the students' understanding of the concept of metallic bonding, allowing them to "see" and "manipulate" the structure of metals.
   • In addition, the teacher should emphasize how metallic bonding is present in our daily lives, through practical examples and real-world applications presented during the lesson.

3. Extra Materials:

   • The teacher should suggest additional study materials so that students can deepen their understanding of metallic bonding.
   • These materials may include explanatory videos, chemistry websites, textbooks, and scientific articles.
   • The teacher may also suggest fixation exercises so that students can practice applying the concept of metallic bonding.

4. Importance in Everyday Life:

   • Finally, the teacher should summarize the importance of studying metallic bonding for everyday life and for industrial applications.
   • It should be reinforced that understanding metallic bonding is fundamental for understanding the properties of metals and how they are used in different contexts, from the manufacture of everyday objects to the production of high-tech materials.
   • The teacher may also emphasize that the study of metallic bonding contributes to the development of important skills, such as critical thinking, problem-solving, and the ability to apply theoretical concepts to practical situations.