Contextualization

Chemistry is the science that studies matter, its properties, how and why substances combine or separate to form other substances, and how substances interact with energy. A fundamental concept within Chemistry is that of chemical bonding, which is the attractive force that holds two atoms or ions together in the construction of a more complex substance. Chemical bonds are of fundamental importance for us to understand how matter is organized and what are the properties of the compounds formed.

Ionic and Covalent Bonds

Ionic or electrovalent bonds occur between a metal and a non-metal. Metal atoms tend to donate electrons from their valence shell, acquiring a positive charge and becoming cations. On the other hand, non-metals tend to receive these electrons to complete their valence shell, acquiring a negative charge and becoming anions.

Covalent bonds, on the other hand, are formed between non-metals, and each of them shares a pair of electrons. The sharing of electrons allows each atom to achieve electronic stability, usually through an octet of electrons in its valence shell.

Relevance of Ionic and Covalent Bonds

Understanding ionic and covalent bonds is essential to comprehend a series of chemical phenomena and the properties of various substances. For example, the table salt we use daily is formed through an ionic bond between sodium and chlorine. On the other hand, the water molecule, essential for life as we know it, is formed through covalent bonds between hydrogen and oxygen atoms. Furthermore, these bonds explain properties such as melting point, boiling point, electrical conductivity, among others.

Atividade Prática

Building Models of Molecules using Ionic and Covalent Bonds

Project Objectives:

1. Understand the difference between ionic and covalent bonds.
2. Identify the structure of the elements involved in these bonds.
3. Build models of simple molecules using ionic and covalent bonds.
4. Understand how ionic and covalent bonds affect the properties of substances.

Project Description:

Students will be divided into groups of 3 to 5 members. The activity will unfold in 3 phases:

1. Research and study on ionic and covalent bonds and the chemical elements involved in these processes.
2. Construction of models of molecules using easily accessible materials.
3. Writing a report on the project.

Required Materials:

1. Styrofoam balls of different sizes or other materials that can symbolize atoms (clay, modeling clay, etc).
2. Toothpicks, to represent the bonds.
3. Paint to color the balls (each type of atom will be represented by a color).
4. Paper, pencils, and/or computers to conduct research and write the report.

Step by Step:

1. Initially, students should conduct a detailed research on ionic and covalent bonds, using the resources suggested in the introduction and others they find. They should pay special attention to the elements involved in these bonds and how these bonds affect the properties of substances.

2. With the acquired knowledge, students should choose 2 molecules: one with an ionic bond and another with a covalent bond.

3. Using the modeling materials, students should build models of these molecules. The balls will represent the atoms and the toothpicks will symbolize the bonds. Different types of atoms should be painted in different colors.

4. During the modeling, students should take photos of the process, which will serve as supporting material and illustration for the report.

5. Finally, students should write a detailed report describing the project. The report should include:

   • Introduction: Contextualizing the theme, relevance of ionic and covalent bonds in the real world, and the objective of this project.

   • Development: Theory on ionic and covalent bonds, detailed explanation of the activities carried out, the methodology used, and presentation of the models of molecules built. The photos taken during the activity should be used in this section to illustrate the process and the project's outcome.

   • Conclusion: Reflect on the importance of ionic and covalent bonds and how the models helped understand these concepts. Students should indicate what they learned from the project and what conclusions they reached.

   • Bibliography: Indicate the research sources used to carry out the project.

This project should be executed over a period of 1 month. Considering the research, the construction of the models, and the elaboration of the report, it is estimated that each student will spend 5 to 10 hours in total.