Unit 5: Metals, non-metals, acids and alkalis

GRADE 6 – Unit 5: Metals, non-metals, acids and alkalis — HIA International - Grade 6 Revision Notes & Topical Questions

5 min read 9 parts Lesson 1 of 8 1 quiz

📚 HIA International - Grade 6 Hub / Topical Revision

0%read

Lesson summary

Unit 5: Properties of materials — HIA INTERNATIONAL notes: Compare metals, non-metals and alloys, separate mixtures, and use indicators and the pH scale to classify acids and alkalis.PropertyMetalsNon-metalsState at room temperaturemost are solidmany are gasesAppearanceshinydullW…

Strong and tough
High melting and boiling points
Good conductors of heat
Good conductors of electricity
Some are magnetic
Evaporation

Part 1 of 7Metals compared with non-metals

Property	Metals	Non-metals
State at room temperature	most are solid	many are gases
Appearance	shiny	dull
When hit or dropped	do not shatter	brittle
Heat conduction	conduct heat energy well	do not conduct heat energy well
Electrical conduction	conduct electricity	most do not conduct electricity
Shaping	malleable and ductile	not malleable or ductile
Sound	sonorous	not sonorous

Part 2 of 7Properties of metals

Properties of metals

Strong and tough

Strong and tough metals do not shatter when dropped, do not crack easily and hold large weights without breaking
Iron is used for bridges because it is strong.

Shiny

Shiny metals are shiny when freshly cut or polished
Gold is used for jewellery because it is shiny.
The surface of most metals becomes dull after a while.

Malleable

Malleable metals can be hammered into shape
Iron is malleable.

Ductile

Ductile metals can be drawn out into wires
Copper is ductile.

Sonorous

Sonorous metals make a ringing sound like a bell when they are hit
Cymbals make a ringing sound when hit.
Bottles and cups also ring but are not made of metal.

High melting and boiling points

High melting and boiling points most metals do not melt easily
Mercury is the only metal that is liquid at room temperature.

Good conductors of heat

Good conductors of heat metals conduct heat energy away from the hand so they feel cold
Steel conducts heat well, which is useful for cooking pans.

Good conductors of electricity

Good conductors of electricity an electric current can flow through them
Copper is used for electrical wiring because it conducts well and is flexible.

Some are magnetic

Some are magnetic iron, steel, nickel and cobalt are magnetic

Part 3 of 7Uses of non-metals

Sulfur

Sulfur added to rubber to make it hard

Oxygen

Oxygen pure oxygen is used in hospitals for people with breathing difficulties

Helium

Helium used to fill balloons

Chlorine

Chlorine kills bacteria, for example when dissolved in water and added to swimming pools

Carbon

Carbon used to purify water and to treat indigestion

Silicon

Silicon used to make computer chips

Part 4 of 7Alloys

Alloy

Alloy a metal mixture made by mixing different metals together and melting them
The atoms of the different metals mix but do not bond together.
The properties of the alloy are different from the metals it contains.

Bronze

Bronze an alloy of copper and tin that is harder than either metal

Steel

Steel an alloy of iron and carbon, so one element is not a metal
Pure iron is not hard enough to be very useful, but steel is much harder.
Adding chromium and nickel gives steel that does not rust, used for cutlery.

Part 5 of 7Separating mixtures

Method

Method use a difference in properties, for example magnetism, boiling point or solubility

Evaporation

Evaporation leaves a dissolved solid behind

Filtration

Filtration holds back an insoluble solid in the filter paper

Condenser

Condenser separates liquids with different boiling points

Part 6 of 7Acids, alkalis and pH

Acids

Acids sour, with pH below 7, and turn litmus red

Alkalis

Alkalis with pH above 7, which turn litmus blue

Neutral

Neutral pH 7, such as water, which turns litmus purple

Universal indicator

Universal indicator shows the pH, from red for strong acids to purple for strong alkalis

Part 7 of 7Working safely with acids and alkalis

Stand up

Stand up so that a spill does not land on you

Wear safety glasses

Wear safety glasses so nothing gets into your eyes

Bottle top

Bottle top place it upside down on the work surface so acid does not get on the surface or dirt into the acid

Replace the top

Replace the top as soon as you have finished, to prevent spills and using the wrong top on the wrong bottle

Spills

Spills wash the area with lots of water, which dilutes the acid

Key terms

Term	Meaning
Alloy	A mixture of metals, or a metal with another element.
Malleable	Can be hammered into shape.
Ductile	Can be drawn out into wires.
Indicator	A substance that changes colour in acids and alkalis.
pH scale	A scale from 0 to 14 that measures how acidic or alkaline a substance is.
Corrosive	Able to destroy living tissue or other materials.

Avoid these mistakes

Saying all metals are magnetic — only iron, steel, nickel and cobalt are magnetic

Saying every metal is solid at room temperature — mercury is a liquid

Saying alloys are compounds — they are mixtures of metals, whose atoms do not bond together

Saying pH 7 is acidic — pH 7 is neutral

Last updated: 12 October 2026