| 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
|
