Welcome to GattPrep!
Hey science explorer! 👋🏽
Take a look around you: the spoon in your cereal, the wire charging your phone, the oxygen you breathe, and the carbon in your pencil. These are all elements—and they fall into three categories: metals, non-metals, and semi-metals (metalloids).
In this lesson, you’ll learn how to recognize and classify these elements and understand what makes metals shiny, non-metals brittle, and metalloids unique. You’ll also see how their properties affect how we use them in real life.
📘 Core Concepts
All elements are broadly grouped as:
| Type | Examples |
|---|---|
| Metals | Iron (Fe), Copper (Cu), Aluminium (Al), Gold (Au) |
| Non-Metals | Oxygen (O₂), Carbon (C), Nitrogen (N₂), Sulfur (S) |
| Semi-metals (Metalloids) | Silicon (Si), Arsenic (As), Boron (B) |
| Property | Metals | Non-Metals | Semi-metals (Metalloids) |
|---|---|---|---|
| Appearance | Shiny (lustrous) | Dull | Shiny or dull |
| Conductivity | Good conductors of heat and electricity | Poor conductors | Moderate conductors (semiconductors) |
| Malleability | Can be hammered into sheets | Brittle (breaks easily) | Brittle or malleable |
| Ductility | Can be drawn into wires | Not ductile | Sometimes ductile |
| State at Room Temp | Solid (except mercury) | Solid, liquid or gas | Solid |
| Density & Strength | Usually high | Usually low | Intermediate |
🔍 How to Identify Them in Real Life
Metals: Feel heavy, shiny, conduct electricity. Used in pots, wires, coins.
Non-Metals: Gases like oxygen or brittle solids like sulfur. Found in air, fertilizers, and charcoal.
Semi-metals: Used in electronics like computer chips (e.g. silicon).
🧪 Where to Find Them on the Periodic Table
Metals: Found on the left and center of the table (e.g. Groups 1–12).
Non-Metals: Found on the right side (except Hydrogen).
Metalloids: Form a “stair-step” line between metals and non-metals.
👨🏽🔬 Examples in Everyday Use
| Element | Category | Use Example |
|---|---|---|
| Aluminium | Metal | Cooking pots, foil |
| Oxygen | Non-metal | Breathing, combustion |
| Silicon | Semi-metal | Computer processors |
| Gold | Metal | Jewelry, electrical connectors |
| Nitrogen | Non-metal | Fertilizers, preserving food |
📐 Sample Problem Walkthrough
🧠 Problem: A student observes a substance that is shiny, conducts electricity, but is brittle. Is it a metal, non-metal, or semi-metal?
✅ Step-by-Step Solution:
Shiny and conducts electricity — these are metal-like properties.
Brittle — not common in typical metals.
Conclusion: The substance is likely a semi-metal.
✔️ Answer: It is a semi-metal (metalloid).
✍🏽 Practice Exercises
1. Fill in the blanks
(a) Metals are good conductors of ______ and ______.
(b) Silicon is a typical example of a ______.
✅ Answers:
(a) heat, electricity
(b) semi-metal / metalloid
2. Match the Element to Its Category
| Element | Category |
|---|---|
| (i) Sulfur | A. Metal |
| (ii) Iron | B. Non-metal |
| (iii) Boron | C. Semi-metal |
✅ Answers:
(i) → B
(ii) → A
(iii) → C
3. Short Answer
Explain one reason why metals are used in electrical wiring.
✅ Sample Answer:
Metals are used in electrical wiring because they are good conductors of electricity, allowing current to flow easily through them.
🌀 Recap
In this lesson, you learned:
Materials are classified into metals, non-metals, and semi-metals.
Metals are shiny, strong, malleable, and conduct electricity.
Non-metals are dull, brittle, and poor conductors.
Semi-metals have properties of both and are important in electronics.
Classifying these materials helps us choose the right one for each job.
💭 Reflection Prompt
Look around your home or school. Choose 3 objects (e.g. spoon, chalk, window glass) and classify each as made from metal, non-metal, or semi-metal. Write down one reason for your classification.
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