- The progress of civilization is linked to the discovery of many metals and non-metals
- Metals were discovered only around 5000 years ago.
- Non-Metals were discovered much later
- Carbon and Sulfur are earliest non metals known to man.
- Even our history is classified corresponding to periods related to discovery of Metals like Stone age,Bronze age , Iron age
- The wealth of a country is determined by the by the amount of gold in its reserve
Common metals are Iron,Copper,Silver,Zinc,Aluminium, Mercury etc.
Common non-metals are Nitrogen,Hydrogen,Oxygen,Sulfur,Chlorine,Phosphorus etc.
Malleable- The property due to which certain elements can be beaten into sheets is called malleability and the elements is called malleable
Ductility- The property of the element due to which they can be drawn into wires is called ductility.
Sonorous– The ringing sound produced by an element is called sonorous
Difference between Metals and non-Metals
- Mercury and Gallium are metals but Liquid at room Temperature
- Sodium,Potassium are metals but they are soft ,and can be cut with a knife
- Sodium Potasium ,Merccure,gallium are metals but has very low melting and boiling point
- Zinc,arsenic,antimony are metals but not malleable
- Bismuth and Tungsten ar emetals but are bad conductors of heat and electricity
- Iodine and Graphite are Non-Metals but lustrous
- Non-metals have low density how ever diamond is as heavier than aluminium
- Non-Metals have low melting and boiing point but Carbon,silicon and boron are exceptons
- Non-metals are bad conductors of electricity but carbon is an exception
Elements-A substance that cannot be broken down into two or different substances by chemical or physical means or by electrolysis is called an element
The smallest unit of a element is known as Atom.
There are total 115 elements of which 92 are naturally occurring and 23 are man made elements
Elements are broadly classified into three categories
a. Metals – 90 metals
b. Non-metals- 18 Non-metals
c. Mettaloids- 7 Mettaloids