Lesson Notes By Weeks and Term v4 - SHS 3
MATTER AND ITS PROPERTIES
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MATTER AND ITS PROPERTIES
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Subject: Chemistry
Class: SHS 3
Term: 1st Term
Week: 9
Grade code: 1.1.1.LI.8
Strand code: 1
Sub-strand code: 1
Content standard code: 1.1.1.CS.1
Indicator code: 1.1.1.LI.8
Theme: PHYSICAL CHEMISTRY
Subtheme: MATTER AND ITS PROPERTIES
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Good morning, class. Today, we are going to explore the "address" of every electron within an atom. Think of an atom as a large house, and the electrons are the residents. Just as every resident has a specific room and floor, every electron has a specific energy level and orbital. Understanding this arrangement, called electron configuration, is the key to unlocking the secrets of chemistry. It explains why some elements are reactive like Sodium (Na), why others are stable like Neon (Ne), why copper is used for our electrical wires, and how chemical bonds are formed. For your WASSCE, this topic is fundamental and questions on it are almost guaranteed.
Introduction: The "Electron Hotel" Analogy
To make this easy, let's imagine the atom is a special hotel for electrons. Hotel Floors: These are the Principal Energy Levels (n = 1, 2, 3, 4...). The ground floor (n=1) has the lowest energy. Types of Rooms on Each Floor: These are the Sublevels (s, p, d, f). `s` sublevels are like single rooms. `p` sublevels are like suites with 3 rooms. `d` sublevels are like executive suites with 5 rooms. Beds in Each Room: These are the Orbitals. Each orbital (a single "box") is like a bed that can hold a maximum of 2 electrons. Guests: The electrons themselves.
Now, let's learn the three main rules for checking guests (electrons) into our hotel (atom). Rule 1: Aufbau's Principle (The "Building-Up" Rule)
This is the most basic rule of our hotel. It states that electrons must occupy the orbitals of lowest energy first before moving to higher energy orbitals.