Contextualization and Introduction

Chemistry is a science that permeates our lives, not only in terms of natural processes, but also in the production of consumer goods and technology. An example of this is metallic alloys, multinational companies produce thousands of tons of products based on them every day. But what are metallic alloys? What makes them so useful and valuable in our society? Our goal with this project is to delve into the universe of metals and their bonds, understand their formation, properties, and applications, for this we will use the concept of 'Metallic Bond' as a starting point.

We start by understanding what the Metallic Bond is. In the periodic table, metals represent the vast majority of elements. These elements have properties quite distinct from others, such as high electrical and thermal conductivity, malleability, and ductility. The metallic bond is a type of bond that occurs between metal atoms and is responsible for these unique properties. The basic idea of this bond is that the electrons in the outermost layer of the metallic atoms are released, forming an 'electron cloud', which is attracted by the positive nucleus of the metallic atoms. This is the classic image of the 'sea of electrons' that defines the metallic bond.

Let's go further, also exploring the science behind metallic alloys. Alloys are mixtures of two or more metals or a metal and a non-metal. They are created to improve the characteristics of metals, such as hardness, corrosion resistance, melting point, among others. A notable example is steel, an alloy of iron with small amounts of carbon, which has much greater strength than pure iron, making it widely used in construction.

Practical Activity: 'Exploring the World of Metals and Their Bonds'

Project Objective

The objective of this project is to stimulate the understanding of the concepts and characteristics of metallic bonds and metallic alloys, as well as their application in the real world. Students will explore the theoretical basis of metallic bonds, create a simple metallic alloy in a laboratory environment, and analyze its properties compared to a pure metal.

Detailed Project Description

The activity will be carried out by groups of 3 to 5 students and is expected to last approximately 15 hours per student.

First, students will delve into the study of metallic bonds and metallic alloys, using the initial resources provided, as well as additional sources they find necessary. Next, they will plan, execute, and analyze a laboratory experiment with the aim of comparing the properties of a pure metal and a metallic alloy. Finally, they will prepare a detailed report presenting their findings and reflecting on their learnings.

In addition to chemistry concepts, the activity also involves math skills, as students will need to calculate proportions, density, and perform other relevant mathematical operations for the project.

Required Materials

• Books and online resources on metallic bonds and metallic alloys
• Chemistry laboratory equipped with a balance, crucible, Bunsen burner, metal tongs or tweezers, samples of pure metals (we suggest lead, due to its low melting point) and elements for the alloy (we suggest tin).
• Safety equipment: safety goggles, lab coat, and gloves
• Note-taking material

Step by Step

1. Research and Study: Start by researching and studying metallic bonds. Use the suggested resources and look for more sources if needed. Make sure you understand the concept and characteristics of metallic bonds.

2. Experimental Plan: Plan the laboratory experiment. The goal is to compare the properties of a pure metal (such as lead) and an alloy you will create (lead and tin). You need to decide which properties you will measure and how. For example, you can measure density, hardness, melting point, etc.

3. Execution: Under the supervision of a teacher, carry out the experimental plan. Make sure to note all important observations.

4. Analysis: Analyze the results of the experiment. Compare the properties of the pure metal and the metallic alloy you produced. What differences did you observe? Are they in line with what you expect from the theory?

5. Report: Prepare a detailed report of the activity. The structure of the report should be: Introduction, Development, Conclusions, and Bibliography.

Project Deliverables and Report Instructions

The main product of the project will be a written report documenting the work done, the findings, and reflections on the process. The report should include:

• Introduction: Provide context on the topic of metallic bonds and their relevance in the real world. Explain the project's objective and what you expected to learn from it.

• Development: Describe the experiment conducted, the methods used, and the results obtained. Include a theoretical discussion of metallic bonds and metallic alloys, as well as the relationship between theory and experimental results.

• Conclusions: Summarize the main points of the project, the learnings obtained, and the conclusions that can be drawn. Reflect on the skills developed through teamwork and the application of theoretical concepts in a practical experience.

• Bibliography: List all sources you used to carry out the project, including books, websites, videos, etc.

The report should be submitted in digital format, in a text document, with a minimum of 2000 words.