Theory:

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:
  
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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:
  
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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:
 
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Non-metals are non-malleable in nature (as they are very brittle, they cannot be drawn into sheets) except carbon.
 
Ductility:
 
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Non-metals are non-ductile in nature (as they are very brittle, they cannot be drawn into wires.)
 
Hardness:
 
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Non-metals are soft except diamond.
 
Valency:
 
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Non-metals have \(4\) to \(7\) electrons in the outermost shell.
 
Conduction:
 
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Non-metals are poor conductors of heat and electricity except graphite.
 
Density:
  
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Non-metals have low density.
 
Sonorous:
 
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Non-metals make a dull sound.
  
Melting and Boiling Points:
 
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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.