6.1 |
Classification of Elements |
Definition |
Molecules are neutral particles made up of two or more atoms. |
Definition |
Element is the simplest form of subtstance and cannot be divided to two or more simpler substances |
Example of element: Zinc, iron, oxygen
Definition |
Compound consists of two or more elements combined chemically |
Example of compound: Salt, shell and sugar
Differences between Metals and Non-metals
Metals |
Characteristics |
Non-metals |
Shiny |
Appearance |
Dull |
Ductile |
Ductility |
Brittle |
Malleable |
Malleability |
Non-malleable |
High |
Tensile strength |
Low (break easily) |
Good |
Electrical conductivity |
Poor (except carbon) |
Good |
Heat conductivity |
Poor |
High |
Density |
Low |
High |
Melting point and boiling point |
Low
|
Both are elements |
Examples of metals and their characteristics |
Aluminium |
- Malleable
- Strong and light
- Grey and shiny
|
Iron |
- Strong
- Malleable
- Magnetic substance
- Good conductor electric
|
Copper |
- Strong
- Rustproof
- Ductile (bends easily)
|
Examples of non-metals and their characteristics |
Iodine |
- Black crystal
- Poisonous
- Antiseptic
|
Chlorine |
- Greenish yellow gas
- Bleaching agent
- Poisonous
|
Carbon |
- Black
- Smooth
- Light
- The only non-metal element that can conduct electricity
|