Properties Of Metals (AQA GCSE Combined Science: Synergy: Physical Sciences): Revision Note
Exam code: 8465
Written by: Stewart Hird
Updated on
Did this video help you?
Properties of metals
Metallic bonds are very strong
This is a result of the strong attraction between the positive metal ions and the negative delocalised electrons within the metal lattice structure:
The properties of a metal
Most metals have high melting and boiling points
There are strong electrostatic forces of attraction between the positive metal ions and the delocalised electrons within the metal lattice
These need lots of energy to be broken
Most metals are malleable
This means they can be hammered into shape
This is because the atoms are arranged in layers which can slide over each other when a force is applied
Examiner Tips and Tricks
When explaining why metals have high melting and boiling points, you must state that metals have a giant structure and that a large amount of energy is needed to break the strong metallic bonds. Saying the bonds are "strong" alone is not enough for full marks.
Properties of alloys
What is an alloy?
An alloy is a mixture of two or more metals or metal with a non-metal such as carbon
Steel is made from iron and carbon
Alloys often have properties that can be very different from the metals they contain
They can be stronger and harder
They are resistant to corrosion or extreme temperatures
These enhanced properties can make alloys more useful than pure metals
Why are alloys harder than pure metals?
Alloys contain atoms of different sizes so the layers become distorted
This makes it more difficult for the layers of atoms to slide over each other, so alloys are usually much harder than the pure metal
Examiner Tips and Tricks
Mark schemes for answers on why alloys are harder than pure metals are very specific. You must refer to atoms or ions throughout your answer, not "particles" or "molecules" because they are not accepted.
Two common mistakes to avoid:
Saying the layers do not slide at all — the correct answer is that they slide less easily
Saying alloys are harder because the bonds are stronger. Hardness comes from the distortion of the layers caused by different-sized atoms
How do metals conduct electricity?
Metals consist of giant structures
Within the metal lattice, the atoms lose their outer electrons and become positively charged metal ions
The outer electrons no longer belong to any specific metal atom and are said to be delocalised
Metals can conduct electricity because the delocalised electrons are able to move through the structure and carry electrical charge
Examiner Tips and Tricks
Questions on why metals conduct electricity are typically worth 3 marks. To get full marks, your answer needs all three of:
The electrons are delocalised (free to move)
They carry electrical charge
They move through the metal structure
Simply stating that metals "have electrons" is not sufficient — you must specify that the electrons are delocalised.
Unlock more, it's free!
Join the 100,000+ Students that ❤️ Save My Exams
the (exam) results speak for themselves:
Was this revision note helpful?