Lesson Plan: Ionisation Energy and Periodic Trends

Grade: 10 Subject: Chemistry

Objective: - Understand the concept of ionisation energy and its significance in chemical reactions. - Identify and explain the factors influencing ionisation energy. - Analyze the trends of ionisation energy on the periodic table. - Calculate and compare first and successive ionisation energies. - Apply the knowledge of ionisation energy to solve problems and assignments.

Materials: - Whiteboard and markers - Periodic table - Handouts with examples and assignments - Calculators

Duration: 3 class periods (45 minutes each)

Procedure:

Day 1:

Introduction (10 minutes): 1. Begin the lesson by asking students if they have heard of ionisation energy and its importance in chemistry. 2. Explain that ionisation energy is the energy required to remove an electron from an atom or ion in the gaseous state. 3. Discuss the significance of ionisation energy in determining the reactivity and chemical behavior of elements.

Factors Influencing Ionisation Energy (15 minutes): 1. Present the factors that influence ionisation energy: atomic radius, nuclear charge, and electron shielding. 2. Explain how atomic radius affects ionisation energy: larger atoms have more loosely held electrons, resulting in lower ionisation energy. 3. Discuss how nuclear charge influences ionisation energy: higher nuclear charge attracts electrons more strongly, increasing ionisation energy. 4. Introduce the concept of electron shielding: inner electrons shield outer electrons from the full effect of nuclear charge, reducing ionisation energy.

Trends in Ionisation Energy (15 minutes): 1. Display the periodic table and explain that ionisation energy generally increases from left to right across a period. 2. Discuss the trend in ionisation energy down a group: ionisation energy generally decreases as you move down a group due to increasing atomic radius and electron shielding. 3. Provide examples of elements with high and low ionisation energies to illustrate the trend.

Assignments (5 minutes): 1. Distribute handouts with examples and assignments related to ionisation energy and factors influencing it. 2. Assign students to complete the handouts for the next class.

Day 2:

Review (10 minutes): 1. Begin the class by reviewing the concepts of ionisation energy, factors influencing it, and the trends on the periodic table. 2. Address any questions or difficulties students may have encountered while completing the assignments.

First Ionisation Energy (15 minutes): 1. Explain the concept of first ionisation energy: the energy required to remove the first electron from an atom. 2. Demonstrate how to calculate first ionisation energy using examples from the handouts. 3. Provide additional examples for students to practice calculating first ionisation energy.

Successive Ionisation Energies (15 minutes): 1. Introduce the concept of successive ionisation energies: the energy required to remove subsequent electrons from an ion. 2. Explain that successive ionisation energies generally increase due to the increased positive charge on the ion. 3. Demonstrate how to calculate successive ionisation energies using examples from the handouts. 4. Provide additional examples for students to practice calculating successive ionisation energies.

Assignments (5 minutes): 1. Assign students to complete additional practice problems on first and successive ionisation energies. 2. Encourage students to use the periodic table and their calculators to solve the problems.

Day 3:

Review and Application (15 minutes): 1. Begin the class by reviewing the concepts of first and successive ionisation energies. 2. Discuss the significance of these energies in predicting the chemical behavior and reactivity of elements. 3. Provide real-life examples where knowledge of ionisation energy is useful, such as explaining why certain elements are more likely to form ions or participate in chemical reactions.

Group Activity (20 minutes): 1. Divide the class into small groups and assign each group an element from the periodic table. 2. Instruct the groups to research and present information about the ionisation energy, factors influencing it, and the trends on the periodic table for their assigned element. 3. Encourage students to use visual aids, such as charts or graphs, to enhance their presentations.

Conclusion (5 minutes): 1. Summarize the key points discussed throughout the lesson. 2. Address any remaining questions or concerns from the students. 3. Emphasize the importance of understanding ionisation energy in chemistry and its applications in various fields.

Assessment: - Evaluate students’ understanding through their completion of handouts and assignments. - Assess their ability to calculate first and successive ionisation energies correctly. - Observe their participation and engagement during the group activity and presentations. - Provide feedback and clarification as needed.