ETA Online Book

Sample lesson Plan

Name of teacher:	Name of school:
Subject: Chemistry	Grade and section: Grade 9
Date of lesson:	Unit of lesson: The Structure of the Atom
Sub-unit of lesson: Discovery of the sub-atomic particles	Topic of lesson: Discovery of the Electron
Competencies: After the lesson Students will be able to Explain the discovery of electron Describe properties of electron Rationale of the topic: most of the properties of the elements like reactivity and bonding depend on the electrons in their atoms. The number of electrons and their arrangements in the atom are also the basis for the classification of the elements in the periodic table. Understanding the experimental procedures of the discovery of electron helps the students to know how scientific methods are used to explore in to the atoms.

Stage

Contents

Teacher’s activities

Student’s activities

Assessment activities

Starter activities(5minutes)

Review of the modern atomic theory

Asking the students to state the postulates of the modern atomic theory
Jotting down the main points of the students’ answers
Ask the to explain the postulates

Students state the postulates giving explanations

Ask how the modern theory amended the Dalton’s atomic theory.

Main activities(28 minutes)

The cathode ray tube Properties of cathode rays

Ask students to predict how scientists discovered particles in an atom.
Give brief explanation of the parts of the cathode ray apparatus and their functions using diagram
Asking students operates and let them reason out
Making students into groups.
Keep the charts of the cathode ray tube 1. with light paddle 2.with +ve and –ve electric plate where they can see.
Give them the following activities

to explain the following observations giving reasons

the rays deflect to the +ve terminal of the electric plate
the light paddle in tube rotates when there are cathode rays
a cross obstacle on the path of the ray casts shadow on the screen
when Thomson used different materials the same rays are produced

They forward their ideas giving reasons.
Students closely observe the diagrams
They make discussion in groups

Each group registers the findings of their discussion and present to the class.

Ask them to describe how the apparatus works

Asking why:

the cathode rays deflect to the positive terminal

the paddle rotates

shadow cast

all substances show the same result

Concluding activities (7minutes)

ask the students to give conclusion of the lesson

Using the diagrams on the charts they may conclude that
Cathode rays move in straight line because the obstacle on their path casts a shadow on the screen
Cathode rays have masses because the paddle was rotated when it was strike by the ray.
Cathode rays are negatively charged because they were attracted to the positive terminal of an electric field
Cathode rays are contained in all substances because when different materials were used in the discharge tube, they show the same result.

Ask the students how from the experiment Thomson came to state

An electron carries a negative charge.
An electron is a fundamental constituent of all matter

Figures

The Periodic Table of the Elements

Bohr’s Atomic Models of the First 18 Elements

Lewis formula of the first 20 elements

Stage	Contents	Teacher’s activities	Student’s activities	Assessment activities
Starter activities(5minutes)	Review of the modern atomic theory	Asking the students to state the postulates of the modern atomic theory Jotting down the main points of the students’ answers Ask the to explain the postulates	Students state the postulates giving explanations	Ask how the modern theory amended the Dalton’s atomic theory.
Main activities(28 minutes)	The cathode ray tube Properties of cathode rays	Ask students to predict how scientists discovered particles in an atom. Give brief explanation of the parts of the cathode ray apparatus and their functions using diagram Asking students operates and let them reason out Making students into groups. Keep the charts of the cathode ray tube 1. with light paddle 2.with +ve and –ve electric plate where they can see. Give them the following activities to explain the following observations giving reasons the rays deflect to the +ve terminal of the electric plate the light paddle in tube rotates when there are cathode rays a cross obstacle on the path of the ray casts shadow on the screen when Thomson used different materials the same rays are produced	They forward their ideas giving reasons. Students closely observe the diagrams They make discussion in groups Each group registers the findings of their discussion and present to the class.	Ask them to describe how the apparatus works Asking why: the cathode rays deflect to the positive terminal the paddle rotates shadow cast all substances show the same result
Concluding activities (7minutes)		ask the students to give conclusion of the lesson	Using the diagrams on the charts they may conclude that Cathode rays move in straight line because the obstacle on their path casts a shadow on the screen Cathode rays have masses because the paddle was rotated when it was strike by the ray. Cathode rays are negatively charged because they were attracted to the positive terminal of an electric field Cathode rays are contained in all substances because when different materials were used in the discharge tube, they show the same result.	Ask the students how from the experiment Thomson came to state An electron carries a negative charge. An electron is a fundamental constituent of all matter

Annexes

Sample lesson Plan