METALS AND NON-METALS
There are very few non-metals as compared to metals. Some of the examples of non-metals are carbon, sulphur, iodine, oxygen, hydrogen, etc. The non-metals are either solids or gases except bromine which is a liquid.
we cannot group elements according to their physical properties alone, as there are many exceptions. For example –
- All metals except mercury exist as solids at room temperature. In Activity 3.5, you have observed that metals have high melting points but gallium and caesium have very low melting points. These two metals will melt if you keep them on your palm.
- Iodine is a non-metal but it is lustrous.
- Carbon is a non-metal that can exist in different forms. Each form is called an allotrope. Diamond, an allotrope of carbon, is the hardest natural substance known and has a very high melting and boiling point. Graphite, another allotrope of carbon, is a conductor of electricity.
- Alkali metals (lithium, sodium, potassium) are so soft that they can be cut with a knife. They have low densities and low melting points.
Elements can be more clearly classified as metals and non-metals on the basis of their chemical properties.
Most non-metals produce acidic oxides when dissolve in water. On the other hand, most metals, give rise to basic oxides.
Next Topic:- What happens when Metals are burnt in Air?