Context

Covalent bonding is one of the most fundamental concepts in the study of chemistry. It is like a dance, where two or more atoms share electrons to achieve a stable state. It is believed to be one of the main reasons for the existence of life, as it is the force that keeps atoms together to form molecules and compounds, which are the building blocks of life.

Traditionally, covalent bonding occurs when two non-metal atoms share electrons, so that both can achieve the noble gas configuration. This means that the atoms involved in the covalent bond can fill their valence shells, resulting in a more stable structure.

However, covalent bonding is not as simple as it seems. There is a variety of different types of covalent bonds, each with its own properties and behavior. For example, a covalent bond can be polar or nonpolar, depending on the electronegativity difference between the atoms involved. Additionally, we also have coordinate covalent bonds, where one atom provides both electrons for the bond.

When thinking about the real world, one may question: why learn about covalent bonds? Well, the answer is simple: they are everywhere! The water molecules we drink, the gases we breathe, the food we eat, the fuels we use in our cars, and even our DNA - all these substances exist because of covalent bonds.

Furthermore, understanding covalent bonds allows us to predict the shape and reactivity of molecules, which is crucial in many areas of science and technology - from medicine and materials to energy and the environment. Therefore, understanding covalent bonding is vital for a variety of careers, from medicine to engineering.

To delve deeper into the subject, students can consult the following resources:

1. Khan Academy (https://pt.khanacademy.org/science/chemistry/chemical-bonds): An online platform that offers free lessons and practical exercises on a variety of chemistry topics, including covalent bonds.

2. Manual da Química (https://www.manualdaquimica.com/quimica-geral/ligacao-covalente.htm): This website provides a detailed overview of covalent bonding, including its types, properties, and examples.

3. YouTube (https://www.youtube.com/watch?v=wyjadqtd0wc): This illustrated video explains covalent bonding in an easy-to-understand way.

Practical Activity: Building Molecules with Covalent Bonds

Project Objective

The objective of the project is to build physical models of molecules with covalent bonds, explore their structural and chemical properties, and understand covalent bonding from a practical and theoretical perspective.

Project Description

Students will be divided into groups of 3 to 5 people. Each group must choose a molecule with a minimum of five atoms, which form covalent bonds to create the molecule's structure. The molecule can be organic or inorganic, as long as its bonds are covalent.

Each group should research and analyze the different types of covalent bonds present in the chosen molecule, exploring concepts such as polar and nonpolar bonds, coordinate covalent bonds, and the valence shell electron pair repulsion (VSEPR) theory.

This project will involve disciplines such as Chemistry and Physics, with Chemistry being responsible for understanding the concepts of covalent bonding and Physics for interpreting the behavior of bonds and their effects on the physical properties of molecules.

The project is expected to take an average of more than twelve hours per student and should be completed within a two-week period. This time will be used for model assembly, research, analysis, and project presentation.

Required Materials

• Styrofoam or clay balls of different colors
• Toothpicks
• Acrylic paints
• Paper, pencil, and eraser
• Computer with Internet access
• Chemistry and Physics books
• Camera or smartphone to document the process

Project Step-by-Step

1. Research: Each group should research the chosen molecule, identifying the types of atoms involved, the number of covalent bonds these atoms form, whether the bonds are polar or nonpolar, and the molecular shape according to VSEPR theory.

2. Model Construction: Using styrofoam or clay balls, students should build a physical model of the molecule, representing the atoms with the balls and the covalent bonds with the toothpicks. Different paint colors will help distinguish the different types of atoms.

3. Analysis and Interpretation: Students must analyze the model, interpreting the covalent bonds and the molecule's structure. They should connect the physical properties of the molecule (melting point, boiling point, polarity, etc.) with its covalent structure.

4. Report: Each group should prepare a detailed report explaining the choice of molecule, the research conducted, the model construction, analysis and interpretation, and the conclusions drawn. Images of the model and records of the construction process should be included. The report should follow the structure: Introduction, Development, Conclusions, and Bibliography.

5. Presentation: Students must present their project to the class, showing the model, explaining the structure and properties of the molecule, and sharing the main points of the report.

Project Deliverables

Each team must deliver the constructed model, the report, and an oral presentation. During the presentation, students should explain the importance of covalent bonding in the structure and properties of the chosen molecule, as well as the application of this molecule in real life.

The written report should include:

1. Introduction: Provide context for the chosen molecule, why it was chosen, and the types of covalent bonds that will be explored.
2. Development: Describe the model construction process, the research work carried out, and the molecule analysis. The report should discuss the different types of covalent bonds and how they affect the physical properties of the molecule.
3. Conclusion: The learnings obtained, the difficulties encountered, and the importance of understanding covalent bonds.
4. Bibliography: Indicate the sources used for the project research.

This project will allow students to understand key concepts of covalent bonding in a practical and theoretical way, enhancing their technical and socioemotional skills.