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📖 Lesson 13 ⏱ ~30 min Year 8 · Unit 2 ⚡ +115 XP

Metals, Non-metals and Metalloids

In 1954, Bell Labs built the first silicon transistor, today over 16 billion transistors fit in every smartphone chip measuring just 1 cm².

Today's hook: In 1954, Bell Labs in the USA produced the first silicon transistor, and by 2023 a single smartphone chip contained over 16 billion of them. Silicon is shiny and hard like a metal, yet it's classified as a metalloid. What makes silicon different, and how do scientists decide where an element fits on the periodic table?
0/5QUESTS
Warm-up
Think First
+5 XP each

Q1 · Think of three everyday objects, what materials are they made from, and are those materials metals or not?

Q2 · If silicon is shiny and hard like a metal but doesn't conduct electricity as well, how do you think scientists decide where to put it?

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Vocabulary · tap to flip
Words You Need
4 terms
Core term Concept Skill Reference
Metal
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Metal
A broad category of elements often linked to conductivity and malleability.
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Non-metal
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Non-metal
A broad category of elements that usually differ from metals in their properties.
tap to flip back
Metalloid
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Metalloid
An element with some metal-like and some non-metal-like properties.
tap to flip back
Property
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Property
A feature used to describe a substance.
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Learning objectives
What you'll master
3 areas

● Know

  • the periodic table includes broad categories
  • metals and non-metals occupy different broad regions
  • metalloids sit between the two broad categories

● Understand

  • categories are linked to broad property patterns
  • not every property must be memorised for every element
  • the table can support comparison

● Can do

  • identify the three broad categories
  • state simple property differences
  • use location language to support comparison
Cross-lesson links: Knowing metals, non-metals and metalloids connects to Lesson 14 (Simple Patterns in the Periodic Table), where reactivity trends run alongside the metal/non-metal divide. It also prepares you for Lesson 16 (Properties of Elements and Why They Matter), where physical and chemical properties drive real materials choices.
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Diagram
Periodic table showing broad regions for metals, non-metals and metalloids
Broad Categories on the Periodic Table Metals Left and centre of table e.g. Fe, Cu, Al, Na Metalloids e.g. Si, B Non-metals Right side of table e.g. O, N, Cl, He
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Broad Regions
The Periodic Table Has Broad Element Categories
+5 XP

Hold a copper wire and a sulfur crystal side by side, the copper bends and conducts electricity; the sulfur shatters and does not, these 2 elements sit on opposite sides of the periodic table, divided into metals, non-metals and a boundary group called metalloids. Metals are found on the left side and in the middle. Non-metals are found on the right side. Metalloids form a staircase-shaped boundary between them.

These categories are not random labels. They predict broad physical and chemical behaviour. Metals tend to conduct heat and electricity, are malleable and ductile, and have a shiny appearance. Non-metals tend to be poor conductors and are often brittle or dull. Metalloids have intermediate properties, most importantly, they can act as semiconductors.

Three Broad Categories in the Periodic Table Fe Cu Na METALS Shiny · conduct · malleable Most elements are metals (~80%) METALLOIDS B, Si, Ge Mixed props semiconductors C N O NON-METALS Dull · poor conductor · brittle Gases + solids + one liquid The boundary between metals and non-metals runs diagonally, metalloids sit along this line
Example

Iron is a metal: it conducts electricity, can be hammered into sheets (malleable) and drawn into wires (ductile), and has a metallic shine. Sulfur is a non-metal: it does not conduct electricity, is brittle and has a dull yellow appearance. Silicon is a metalloid: it conducts electricity only under certain conditions, which makes it perfect for computer chips.

Real-world anchor

Australian silicon industry: Australia is a significant producer of high-purity silicon used in solar panels and electronics. Silicon's position as a metalloid, with semiconductor properties, makes it essential for the renewable energy sector and the tech industry.

Watch out

'All solids are metals.' This is wrong. Sulfur, carbon and iodine are all solids at room temperature, but they are non-metals. State of matter (solid, liquid, gas) is independent of metal/non-metal classification. Always check properties like conductivity and malleability, not just whether the substance is solid.

Mix & match+8 XP

Sort each element into the correct category.

Items
Iron (Fe)
Sulfur (S)
Silicon (Si)
Copper (Cu)
Oxygen (O)
Aluminium (Al)
Carbon (C)
Germanium (Ge)
Categories
Metal
conducts heat and electricity, shiny
Non-metal
poor conductor, brittle or dull
Metalloid
properties in between, semiconductor
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Stop & Check, Categories
Quick Check
+5 XP

Work it out: Use the information in "Categories" to solve a simple problem. What is your answer?

💡 Your brain remembers better when you write it out yourself.

Match each property to whether it describes metals or non-metals.
  • Conducts heat well
  • Brittle
  • Shiny
  • Dull
  • Non-metal
  • Non-metal
  • Metal
  • Metal
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Common Traits
Metals Share Some Common Physical Properties
+5 XP

At this level, metals are described using properties such as conductivity, lustre, malleability and strength. These properties help explain why metals are used in wires, structures and everyday technology. The point is not memorising every metal, but understanding the property-use link.

When you see a material used for wiring, ask: is it conductive? When you see a material used for building frames, ask: is it strong? The periodic table tells you which elements are likely to have these properties based on their category.

Key Properties of Metals Shiny / lustrous reflects light Conducts electricity free electrons move Malleable can be hammered flat heavy light High density heavy for their size
Example

Copper is used for electrical wiring because it is an excellent conductor of electricity and can be drawn into thin wires without breaking. Iron is used for building frames because it is strong and can support heavy loads. Gold is used for electronic contacts because it does not corrode. In each case, the use follows directly from the property.

Real-world anchor

Australian steel production: BlueScope Steel operates one of Australia's largest steelworks at Port Kembla. Steel, an iron alloy, is chosen for construction because of its strength and durability. Understanding why metals have these properties is essential for Australia's building and manufacturing industries.

Watch out

'Shininess alone makes something a metal.' Not true. Some non-metals can be shiny, iodine crystals have a metallic lustre but are poor conductors. Some metals can be dull, iron rust loses its shine but is still a metal. Always use multiple properties (conductivity, malleability, ductility) to classify, not just appearance.

Which one does NOT belong with the others?
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Comparison
Non-metals and Metalloids Extend the Comparison
+5 XP

Non-metals often differ from metals in predictable ways, while metalloids show a mixed picture. Non-metals are generally poor conductors, brittle when solid, and have lower melting points than metals. Metalloids have properties that fall between metals and non-metals, they may conduct electricity under some conditions but not others.

This broad comparison helps you see that the periodic table is not random. Position connects to category, and category connects to broad properties. You only need descriptive comparison at this level, not advanced trend analysis.

Non-metals vs Metalloids NON-METALS Dull appearance (no shine) Poor conductors of electricity Brittle when solid (crumbles) Low density (lighter) e.g. C, N, O, S, Cl vs METALLOIDS Some metallic appearance Semiconductors (partial conductors) Mixed brittleness Sit on staircase boundary e.g. B, Si, Ge, As, Te
Example

Oxygen is a non-metal gas that supports combustion but does not conduct electricity. Carbon is a non-metal solid that exists as soft graphite (used in pencils) and hard diamond (used in cutting tools). Silicon is a metalloid that conducts electricity only when heated or treated specially, this makes it ideal for computer chips and solar cells.

Real-world anchor

Australian solar industry: Companies like 5B and SunDrive use silicon, a metalloid, to manufacture solar panels. Silicon's semiconductor properties allow it to convert sunlight into electricity efficiently. Australia's solar industry is one of the fastest-growing sectors of the economy, built on understanding metalloid behaviour.

Watch out

'Non-metals are all gases.' They are not. Carbon, sulfur and phosphorus are solid non-metals. Bromine is a liquid non-metal. Only some non-metals are gases at room temperature. State of matter does not determine whether something is a metal or non-metal, properties and periodic table position do.

True or false?
All metals are good conductors of electricity.
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Activity, using: Non-metals and Metalloids
Activity 2
+5 XP · activity

Choose one likely use for a metal and explain it from broad properties rather than memorised fact lists.

Choose one metal and explain one likely use using a broad property.
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Table Use
Category Helps with Practical Judgement
+5 XP

If you know a substance is a metal, that gives a useful first clue about likely properties and uses.

This is the beginning of the property-use block that becomes more important at the end of the unit.

A strong answer uses category as evidence, not as a meaningless label.

Match each broad category to a typical property.
  • Metal
  • Non-metal
  • Metalloid
  • Often poor conductor and brittle when solid
  • Shows mixed metal-like and non-metal-like properties
  • Often conductive and malleable
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Activity, using: Reasoning
Activity 1
+5 XP · activity

Classify a set of named elements as metal, non-metal or metalloid using a classroom periodic table.

Fill in the blanks with the correct category.

Iron is a , sulfur is a , and silicon is a .

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Try It, Reasoning
Material Classifier
+5 XP

Use the Material Classifier interactive below. What is one thing you learned from using it?

After using the Material Classifier, write one sentence about how knowing a material's category can help predict its use.
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From the lesson
Interactive
Interactive: Material Classifier
Reflect
Revisit your thinking
reflect

At the start of this lesson, you were asked about silicon being shiny and hard like a metal yet classified as a metalloid, and how scientists decide where an element fits on the periodic table.

Now that you have worked through everything, write your answer below. How has your thinking changed, and what surprised you most?

Interactive Tool, Elements, Compounds & Mixtures Open fullscreen ↗
Non-metals are generally located on which side of the periodic table?
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Quick check
Which broad category is usually linked to conductivity and malleability?
+10 XP
2
Quick check
What is a metalloid?
+10 XP
3
Quick check
Why are broad categories useful?
+10 XP
4
Quick check
Which statement is strongest?
+10 XP
5
Quick check
Which is the weakest explanation?
+10 XP
Short answer · explain in your own words
Show your reasoning
3 questions
Understand Core 4 marks

Q1. Compare metals, non-metals and metalloids at a broad this level level.

Apply Core 4 marks

Q2. Explain why broad category can help a scientist make a first guess about an element’s use.

Analyse Core 5 marks

Q3. Why is a property-based explanation stronger than just naming the category?

Model answers (click to reveal)

Model Answers

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Multiple Choice

1: A. Metals are broadly linked to conductivity and malleability.

2: C. A metalloid shows some metal-like and some non-metal-like properties.

3: D. Broad categories help connect position with likely properties.

4: B. The categories help organise broad comparisons of element properties.

5: A. That explanation gives no property-based reason.

Short Answer 1

Metals are a broad category often linked to conductivity, malleability and lustre. Non-metals differ from metals in broad property patterns. Metalloids show some metal-like and some non-metal-like features.

Short Answer 2

Broad category can help because it gives a first clue about likely properties. Those properties can then help explain why an element may be suitable for certain uses.

Short Answer 3

It is stronger because science explanations need reasons. Naming the category alone is shallow, but linking category to properties and then to use gives a clearer scientific explanation.

Model answers (click to reveal)

Model Answers

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Multiple Choice

1: A. Metals are broadly linked to conductivity and malleability.

2: C. A metalloid shows some metal-like and some non-metal-like properties.

3: D. Broad categories help connect position with likely properties.

4: B. The categories help organise broad comparisons of element properties.

5: A. That explanation gives no property-based reason.

Short Answer 1

Metals are a broad category often linked to conductivity, malleability and lustre. Non-metals differ from metals in broad property patterns. Metalloids show some metal-like and some non-metal-like features.

Short Answer 2

Broad category can help because it gives a first clue about likely properties. Those properties can then help explain why an element may be suitable for certain uses.

Short Answer 3

It is stronger because science explanations need reasons. Naming the category alone is shallow, but linking category to properties and then to use gives a clearer scientific explanation.

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Recap
Quick Review

● Categories

Metals, non-metals and metalloids are broad table categories.

● Properties

Broad property patterns help with comparison.

● Use

Property-based reasoning is stronger than labels alone.

● Next

The next lesson looks at simple periodic patterns.

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