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. A physical property can cause a physical change but not a chemical change.
Let us see some of the physical properties of Non-metals:
- Melting point and boiling point
Most of the non-metals exist in all three states of matter at room temperature. For example, carbon (solid), bromine (liquid) and chlorine (gas).
Non-metals are non-lustrous (as they have no metallic lustre and do not reflect light) in nature, except iodine and diamond.
Non-metals are non-malleable (as they are very brittle, they cannot be drawn into sheets)in nature, except carbon.
Non-metals are non-ductile (as they are very brittle, they cannot be drawn into wires) in nature.
Brittle nature of non-metal
Non-metals are soft except diamond.
Non-metals have \(4\) to \(7\) electrons in the outermost shell.
Electronic configuration of non-metal
Non-metals are poor conductors of heat and electricity except graphite.
Non-metals have low density.
Non-metals make a dull sound.
Melting and Boiling point:
Non-metals have low melting and boiling points except sodium and potassium, which have low melting and boiling points.
Low melting point of non-metal
The materials which generally possess the above properties are called Non-metals.
Oxygen, carbon, sulfur, hydrogen, phosphorous, nitrogen, chlorine etc.