Contextualization

Molecular Geometry is an aspect of chemistry that studies the three-dimensional shapes that molecules take. Through this theory, we can predict the shape that a molecule will take, knowing only its formula. To do this, we take into account the valence electrons of the central atom, and how they orient themselves in space to maximize the repulsion between them.

The structure that atoms adopt in a molecule, as well as the distribution of their electrons, is crucial to understand their physical and chemical properties. For example, water is a polar molecule because its hydrogen atoms are arranged at an angle that allows the molecule to have a positive and a negative side, which would not happen if the water molecule were linear.

Beyond theory, molecular geometry has fundamental practical applications. An example of this is the pharmaceutical industry: the molecular geometry of a drug directly influences its effectiveness, as often it is the shape of the molecule that determines whether it will or will not be able to act on a specific biological receptor. Similarly, molecular geometry is vital in the design of new materials, in the development of more efficient fuels, in the understanding of biological processes, among many other fields.

Practical Activity: "The Molecules Around Us: Understanding their Shape and Function"

Project Objective

To understand the concept of molecular geometry and how it influences the properties of substances, through modeling common molecules in our daily lives.

Project Description

Students will be divided into groups of 3 to 5 members and will be tasked with choosing, researching, and building models of five different molecules found in everyday products or substances (such as water, table salt, sugar, ethanol, acetic acid, among others).

After construction, they should analyze the geometry of each molecule, discussing how this affects their properties and uses in everyday life. Finally, they should produce a report describing their findings.

Required Materials

• Toothpicks
• Gummy bears or marshmallows
• Computer with Internet access
• Chemistry textbook

Step by Step

1. The groups will research the molecules of the chosen substances, using their chemistry textbooks, reliable websites, and other resources as a basis, analyzing their structures and properties.

2. Next, they will build models of the molecules using toothpicks to represent chemical bonds and gummy bears or marshmallows to represent the atoms.

3. After assembly, students should analyze the geometry of the constructed molecules, discussing how the shape affects the substance's properties.

4. The groups should then prepare a 15-minute oral presentation, where they will share their findings with the class, explaining which molecules they chose, what their geometries are like, and how this impacts their properties and uses.

5. Finally, the groups should produce a report on the project, containing the sections of Introduction, Development, Conclusions, and Bibliography.

   • The Introduction should contextualize the theme of molecular geometry and its relevance, as well as the project's objectives.
   • The Development should describe the theory behind molecular geometry, detail the activity carried out, the methodology used in building the models, and the discussions held on the properties of the molecules.
   • The Conclusions should summarize the main points of the project, the lessons learned, and the conclusions about the importance of molecular geometry in understanding the properties of substances.
   • The Bibliography should indicate the research sources used, whether books, websites, videos, etc.

The project must be completed and submitted within one week after its presentation in the classroom.