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The elements in the periodic table are classified as metals and non-metals based on their physical and chemical properties. There are around \(95\) metals and \(17\) non-metals in the periodic table.
Non-Metals are electronegative elements where they gain electrons to form a stable configuration.
Physical properties of non-metals:
A physical property can be observed and measured without altering the sample's chemical identity. In other words, a physical property can cause a physical change but not a chemical change.
Let's see some of the physical properties of non-metals.
- State
- No- Lustre
- Non- Malleability
- Non- Ductility
- Hardness
- Valency
- Conduction
- Density
- Sonorous
- Melting and Boiling Points
State:
![shutterstock_620155748.jpg](https://resources.cdn.yaclass.in/42015839-6939-4235-9658-2b79672c186c/shutterstock620155748w300.jpg)
Most of the non-metals exist in all three states of matter at room temperature. For example, carbon (solid), bromine (liquid) and chlorine (gas).
Lustre:
![shutterstock_1216122388.jpg](https://resources.cdn.yaclass.in/d177a9b7-1f01-4321-9d53-07364aefa5bf/shutterstock1216122388w300.jpg)
Non-metals have no lustre in nature (as they have no metallic lustre and do not reflect light) except iodine, diamond.
Note: Diamond is a non-metal which is hard and lustre.
Malleability:
![shutterstock_1282880224.jpg](https://resources.cdn.yaclass.in/c76a6bde-ee23-46da-82d5-2fe055abd5f9/shutterstock1282880224w300.jpg)
Non-metals are non-malleable in nature (as they are very brittle, they cannot be drawn into sheets) except carbon.
Ductility:
![shutterstock_1402610447.jpg](https://resources.cdn.yaclass.in/25223fd6-6276-40ae-baff-954641a4da3e/shutterstock1402610447w300.jpg)
Non-metals are non-ductile in nature (as they are very brittle, they cannot be drawn into wires.)
Hardness:
![shutterstock_787962505.jpg](https://resources.cdn.yaclass.in/a233e0e8-6934-4619-b645-3be3d7bc8f1e/shutterstock787962505w300.jpg)
Non-metals are soft except diamond.
Valency:
![shutterstock_152410307.jpg](https://resources.cdn.yaclass.in/c730e571-6f72-4a26-b113-3c322f3781d2/shutterstock152410307w300.jpg)
Non-metals have \(4\) to \(7\) electrons in the outermost shell.
Conduction:
![shutterstock_675222982.jpg](https://resources.cdn.yaclass.in/e2cd416f-eef9-4e26-a739-040482ba8ffa/shutterstock675222982w300.jpg)
Non-metals are poor conductors of heat and electricity except graphite.
Density:
![shutterstock_591790736.jpg](https://resources.cdn.yaclass.in/aee56ea4-7f96-46fc-97b7-6ed0cdfbe8b9/shutterstock591790736w300.jpg)
Non-metals have low density.
Sonorous:
![shutterstock_1057477238.jpg](https://resources.cdn.yaclass.in/b287eb15-1275-4e44-9f9c-949fc316ce6f/shutterstock1057477238w300.jpg)
Non-metals make a dull sound.
Melting and Boiling Points:
![shutterstock_757337167.jpg](https://resources.cdn.yaclass.in/d7d3f957-9006-4940-ad97-b559aeaf8693/shutterstock757337167w300.jpg)
Non-metals have low melting and boiling points except sodium and potassium, which has a low melting and boiling points.
The materials which generally possess the above properties are called Non-metals.
Example:
Oxygen, carbon, sulfur, hydrogen, phosphorous, nitrogen, chlorine etc.