There are 23 elements which can be called as non metals but there is a type of element known as metalloids which shows chemical behaviour like non metals but show 

Non metals have been shown to have lower density than metals and the electronegativity is seen among them to be from high to moderate. There is no particular definition for a non metal so they have to be determined and classified based on their properties. Some of the easily identified no metals are :-

• Gases – Oxygen, nitrogen, hydrogen and sulphur. 
• Halogens – Mainly the halogens corrosive in nature , like fluorine, chlorine, bromine and iodine. 
• Noble Gases -Neon, argon, krypton, xenon and radon. 
• Etc. 

Properties of non metals. 

The properties of non metals can be divided into two parts. Therefore the physical and chemical properties of non metals are :-

Physical properties

• Not Malleable – Malleability is known as that property of an element which allows it to be hammered and turned into thin sheets. They tend to break while getting hammered.
• Not ductile – Ductility is known as the property of an element which allows it to be turned into wires. Non metals cannot be drawn into wires . 
• Conductivity – Non metals are not only a bad conductor of electricity but also a bad conductor of heat. This means that the heat and electricity cannot easily pass through a non metal. 
• Non Lustrous – Lustre is known as the shine on the outer surface of an element. Non metals are not lustrous and are dull in appearance.
• Tenacity – The ability of holding weight is known as the tensile strength of the element. Non metals are known for having a low tensile strength. 
• Non sonorous – This means that the non metals would not make sound on getting hit. 
• Soft – Non metals are not very hard and can be cut by a knife itself. 

Chemical properties of non metals 

• Electronegativity – Every element and its atoms need to give or take a certain number of elections to form a chemical bond with other elements. The tendency of an atom to gain electrons is known as electronegativity. Non metals have moderate to high levels of electronegativity. 

•  Chemical bonds – A chemical bond can be defined as the attraction between two elements by the virtue of sharing of electrons. Non metals usually form covalent bonds between themselves and form ionic bonds between them and metals. 
• Loss of electrons – This may be negative or positive in cases of non metals. 
• Oxides – Oxides are chemical compounds formed when an element reacts with oxygen. Oxides have one oxygen atom and another atom if the element . These non metallic oxides are acidic in nature. 
• Solution with water –  The aqueous solution will turn a litmus paper from blue to red. 

Examples of non-metal which are widely used

Here are some of the non metals :- 

• Hydrogen – It is a non-metal found in gaseous form and is denoted as H. 

• Bromine – It is a liquid non-metal which can be denoted as Br. 

• Nitrogen – It is denoted as N and is found in the atmosphere in gaseous form. 

• Oxygen – It is our life sustaining gas and it is denoted by the letter O. 

• Iodine – This non metal is found in solid form and is denoted as I. 

• Carbon – Denoted as C , carbon is found in solid state mostly .

• Silicon – These are very useful in making sand and other products. It is denoted as Si and is found in solid form in the atmosphere. 

• Phosphorous – It is a solid non metal and is denoted as P.

Conclusions

There are many chemical properties of non metals along with physical qualities which differentiate them from metals and other elements. These properties allow them to be distinguishable and be used for various other activities. Apart from the 23 determined elements there are other elements too for the contention of being non metals.