Physical Properties of Metals and Non-metals
Elements can be broadly divided into two categories: metals and non-metals. They differ both in physical and chemical properties.
1. Malleability and Ductilily
Metals are malleable. They can be beaten into thin sheets. They are also ductile and can be drawn into wire (except a few metals like Na, K).
Non-metals are neither malleable nor ductile. For example, coal (carbon) and sulphur.
2. Metallic Lusture
All the metals show metallic lusture.
Non-metals do not show any metallic lusture.
3. Hardness
Metals are generally hard.
Non-metals are soft in comparison to metals.
4. Physical State
Metals exist in solid and liquid states.
Non-metals exist in solid, liquid and gaseous states.
5. Sonorous
Metals are sonorous and produce characteristic metallic sound when struck.
Non-metals are non sonorous.
6. Density
Metals have high density.
Non-metals have low density.
7. Electrical Conductivity
Metals are good conductor of electricity.
Non-metals are bad conductor of electricity.
Points to Note
- Mercury is the only metal and bromine is the only non-metal which exist in liquid state at room temperature.
- Graphite and iodine possess metallic lusture though they are non-metals.
- Sodium metal is soft like wax and it can be cut with a knife.
- Gallium metal would melt if kept on our palm.
- Gold and silver are the most malleable and ductile metals.
- Diamond is a better conductor of heat than copper but poor conductor of electricity.
- Graphite is the only non-metal which is a good conductor of electricity but poor conductor of heat.
- Gold, silver, platinum and copper are found in the free state. This is because of their poor reactivity as compared to other metals.