Lesson Plan | Traditional Methodology | Planar Isomerism

Objectives

Duration: 10 - 15 minutes

The purpose of this stage is to introduce students to the concept of plane isomerism, highlighting the importance of recognizing and classifying different types of isomers. It is essential that students understand these basic concepts so that they can apply this knowledge to solve more complex problems related to organic chemistry. This stage establishes the necessary theoretical foundation for the practical and problem-solving activities that will follow in the class.

Main Objectives

1. Recognize the main plane isomerisms.

2. Classify the different types of plane isomerism, such as functional and chain.

3. Verify the number of plane isomers in a given compound.

Introduction

Duration: ⏱️ Duration: (10 - 15 minutes)

 Purpose: The purpose of this stage is to introduce students to the concept of plane isomerism, highlighting the importance of recognizing and classifying different types of isomers. It is essential that students understand these basic concepts so that they can apply this knowledge to solve more complex problems related to organic chemistry. This stage establishes the necessary theoretical foundation for the practical and problem-solving activities that will follow in the class.

Context

離 Context: Start the class by explaining that Isomerism is a crucial phenomenon in Organic Chemistry. It describes compounds that, despite having the same molecular formula, exhibit different structures and consequently distinct properties. Use simple examples, such as alcohol and ether, to highlight that these compounds have identical molecular formulas but different chemical and physical structures and properties.

Curiosities

 Curiosity: Isomerism has practical applications in the real world. For example, thalidomide, a drug used in the 1950s to treat morning sickness, has two isomers: one that is therapeutic and another that causes congenital defects. This example illustrates the importance of understanding isomers and their properties, emphasizing how small changes in molecular structure can have significant real-world impacts.

Development

Duration: ⏱️ Duration: (40 - 50 minutes)

 Purpose: The purpose of this stage is to deepen students' knowledge about the different types of plane isomerism, providing concrete and detailed examples for each type. Thus, it is expected that students will be able to identify and differentiate plane isomers, applying these concepts in solving specific problems. Practice with selected questions helps consolidate learning and verify students' understanding of the topic.

Covered Topics

1. 離 Chain Isomerism: Explain that it is a type of isomerism where the isomers have the same molecular formula but different arrangements in the carbon chain. Use examples such as butane (n-butane) and isobutane (methylpropane) to illustrate the difference. 2. 離 Position Isomerism: Detail that it occurs when the isomers differ in the position of a functional group or an unsaturation along the carbon chain. For example, 1-butanol and 2-butanol (butylic alcohol) differ by the position of the hydroxyl group (-OH). 3. 離 Functional Isomerism: Explain that it is when the compounds have the same molecular formula but belong to different organic functions. Examples include methanol (alcohol) and dimethyl ether (ether). 4. 離 Compensatory Isomerism (Metamerism): Address that it occurs in compounds with divalent functional groups, where the isomers differ by the distribution of carbon atoms around the functional group. A classic example is the difference between ethyl ether (diethyl ether) and methylpropyl ether. 5. 離 Tautomeric Isomerism: Explain that it is a special case of functional isomerism where the isomers coexist in dynamic equilibrium, such as in the case of aldehyde and enol (ketone) with the molecular formula C3H6O.

Classroom Questions

1. Given the compound C4H10, identify and draw the possible chain isomers. 2. For the compound C3H8O, indicate and draw the possible functional isomers. 3. Consider the compound C5H10. How many position isomers can be formed and what are their structures?

Questions Discussion

Duration: ⏱️ Duration: (20 - 25 minutes)

 Purpose: The purpose of this stage is to review and consolidate the knowledge acquired by students, clarifying doubts and reinforcing the concepts taught. The detailed discussion of the answers and student engagement in reflections and questions helps to solidify the content, ensuring a better understanding and practical application of the concepts of plane isomerism.

Discussion

• 離 Discussion of Questions:

• Identification and Drawing of Chain Isomers for C4H10: Explain that the possible chain isomers for the compound C4H10 are n-butane (CH3-CH2-CH2-CH3) and isobutane (or methylpropane, (CH3)2CH-CH3). Highlight that both have the same molecular formula but different arrangements in the carbon atom chain.

• Functional Isomers for C3H8O: For the compound C3H8O, the possible functional isomers are propyl alcohol (1-propanol, CH3-CH2-CH2OH) and methyl-ethyl ether (CH3-O-CH2-CH3). Explain that, despite having the same molecular formula, they belong to different organic functions - one is an alcohol and the other is an ether.

• Position Isomers for C5H10: In the case of the compound C5H10, which can be an alkene, the possible position isomers include 1-pentene, 2-pentene (cis and trans). Explain that the position of the double bond between the carbon atoms changes, creating different isomers.

Student Engagement

1.  Student Engagement: 2. Ask: What difficulties did you encounter when trying to identify the chain isomers? 3. Reflect: How can the position of a functional group alter the physical and chemical properties of a compound? 4. Discuss: Why is it important to understand functional isomerism in practical contexts, such as in the pharmaceutical industry? 5. Ask: Did anyone find more than two isomers for any of the compounds? If so, which ones and why? 6. Reflect: How can understanding plane isomerism aid in advanced studies of organic chemistry and in practical applications?

Conclusion

Duration: 10 - 15 minutes

The purpose of this stage is to recap and consolidate the main concepts covered during the class, ensuring that students have a clear and cohesive understanding of the topic. It also serves to highlight the practical importance and relevance of the concepts learned, encouraging students to reflect on the application of knowledge in real contexts.

Summary

• Isomerism is a phenomenon where compounds with the same molecular formula have different structures and properties.
• Chain isomerism occurs when there are different arrangements in the carbon atom chain.
• Position isomerism is when the position of a functional group or unsaturation differs within the carbon chain.
• Functional isomerism happens when compounds belong to different organic functions, despite having the same molecular formula.
• Compensatory isomerism (metamerism) occurs in compounds with divalent functional groups, with different distributions of carbon atoms.
• Tautomerism is a functional isomerism where the isomers coexist in dynamic equilibrium.

The lesson connected theory to practice by providing concrete and detailed examples for each type of plane isomerism, in addition to proposing questions that encouraged students to apply the concepts learned in practice. This helped reinforce the understanding of the different types of isomers and their properties, showing how these concepts are applicable in real-world situations, such as in the pharmaceutical industry.

Understanding isomerism is crucial for various practical applications, such as drug synthesis, where the difference between isomers can mean the efficacy or toxicity of a compound. A striking example is that of thalidomide, where one isomer is therapeutic and the other causes congenital defects. This knowledge is vital for future careers in chemistry, biology, and related fields.