1. Year 9 Science
Important materials

2. Elements – The Periodic Table
Year 9 Science

3. Elements
Year 9 Science
Pure substances can be further classified as elements and compounds. Elements are the building blocks of all other substances. Elements consist of atoms of the same type and are represented separately on the periodic table. Elements cannot be broken down further by chemical processes. Elements are classified according to their properties metals or non- metals or metalloids

4. 2.1 Metals, non metals and metalloids
Year 9 Science
Metals:
Lustrous-shine when polished
Malleable- can be bent without breaking
Ductile-stretched into wires
Can conduct electricity and are thermal/heat conductors
Solid at room temperature
Very dense
Form basis of our technology and art-horseshoes and swords, electrical wiring
PURE METALS
Are too soft to be used alone

5. ALLOYS MOST METALS AROUND US ARE ALLOYS- A metal with another element
Usually improves the properties of the original base metal
Makes it stronger etc
i.e Steel- base metal iron but steel much stronger than iron
Gold is usually silver or copper added to pure gold to make it stronger for jewellery- the carat scale in gold is the amount of pure gold to other metals-24 carat is pure gold

6. Found naturally as gases in the air
Non Metals
Year 9 Science
Found naturally as gases in the air
A few are solids-sulfur in volcanoes
PROPERTIES OF METALS
POOR CONDUCTORS
BRITTLE
LOW MELTING POINTS
DULL TO LOOK AT
CARBON
Unusual as an element because generally combines with other elements to form compounds
Over 90% of all known compounds contain carbon
Pure carbons in various forms-allotropes
Amorphous carbon
Diamond
graphite

7. Elements – The Periodic Table
Year 9 Science
The periodic table organises the elements systematically – in patterns that relate to their properties.
The elements on the left hand side of the periodic table all share similar properties. Almost all:
Are shiny when freshly cut and can be polished
Have high melting and boiling temperatures
Can be easily bent and stretched
(all) conduct electricity well
These elements are all metals.

8. Elements – The Periodic Table
Year 9 Science
In between the metals and non-metals is a section of elements that share metal and non-metal properties. These are called metalloids and are widely used in the semiconductor industry to produce materials used for ICT products. The metalloids include silicon, arsenic, germanium, antimony, …