Non Metal Properties - Class X

 Non Metal:

• An element  which gains or share  one or more electrons to form chemical compound  is called Non metal.  

Non metal

1. An non-metal gains electrons from metal to form ionic compound.
2. An non-metal  share electrons with other non-metal  to form covalent compounds

Thus , Nonmetal forms compound by using electrovalent as well as  covalent bonds.

• There are 22  Non-metals out of 118 elements

• In periodic table , Non metals are kept  in groups 14  to 17.

• The major non metals in the earth’s crust  in decreasing order of their abundance are : oxygen, silicon, phosphorus, and sulphur .

Importance of Non Metals:

• Though Non-metals are small in number but they play vital  role in our life. Life would not have been possible without non- metals.

Carbon:

• Carbon is one of the most important non- metal . Proteins, fat, carbohydrates, vitamins , enzymes are compounds of carbon which are essential for living organism.

Oxygen:

• Oxygen is most abundant non-metal in the earth crust. its constituent in earth crust  is about  50%   and  in   air is about 22% .

• oxygen is essential part of our life. Presence of oxygen in the air is essential for breathing to maintain life. Oxygen is also essential for combustion of fuel to release energy.

Nitrogen:

• Nitrogen is essential for life cycle. Due to inertness It reduce the rate of combustion and make it safe. Nitrogen is main constituent of air  of about 75%.

Sulphur :

• Sulphur is present in part of living organism.  e.g  hair, garlic, onion, wool contain sulphur .

Physical Properties of Non-metals:

• Out of 22 non-metals , 10 non-metals are solid,  11 non-metals are gas and only one non-metals ( Bromine ) exist in liquid at room temperature.

•  Non-metals are neither malleable nor ductile but these are brittle.

• Non-metal do not conduct heat and electricity . 
• Exception: carbon in form of graphite is good conductor of electricity.

•  Non-metals are soft in nature .
• Exception: carbon in form of diamond is hardest substance known to us .

•  Non-metals  are dull in appearance i.e these are not lustrous.
• Exception: Iodine is lustrous .

• Non-metals have low melting and boiling points. 
•  Exception: diamond is a nonmetal whose melting point is more than 3500 ^oC.

• Non-metals  have low density. e.g density of sulphur is 2g/cm³ 
•  Exception:  density of carbon in form of diamond is too high.

• Non-metals are non-sonorous.

• Non-metals have many different colour.

e.g .  sulphur is  yellow,  phosphorous is  white or red,  graphite is black , chlorine is yellowish green, bromine is yellow liquid,  hydrogen, nitrogen, oxygen are colourless gases.

Chemical Properties of Non-metals :

Reaction With Oxygen :

• Non-metals react with oxygen on burning to form acidic or neutral oxides.

• e.g. carbon , nitrogen and sulphur, phosphorus   react with oxygen to form acidic oxide  while Hydrogen   react with oxygen to form neutral oxide.

C (s) + O₂ (g)  → CO₂ (g)

S (s) + O₂ (g)  → SO₂ (g)

4P (s) + 5O₂ (g)  → 2 P₂O₅ (g)

2H₂(g) + O₂ (g)  → 2H₂O

• Acidic oxide is also called acid anhydride.

• Acidic oxide of non-metals like CO₂  and SO₂  dissolve in water to form acid  which turn blue litmus red.

CO₂ (g) + H₂O (aq) → H₂CO₃ (aq)

SO₂ (g) + H₂O (aq) → H₂SO₃ (aq)

• Neutral oxides:  CO, N₂O, NO, H₂O  are neutral oxide which do not dissolve in water to form acid.

• When carbon is burnt in an insufficient oxygen ,then  carbon mono oxide is formed.

2C (s) + O₂ (g)  → 2CO(g)

Reaction with Water:

• Non-metals do not react with water to form hydrogen gas .it is because non-metals do not give electrons to reduce hydrogen ions of water into hydrogen gas.

Reaction With Acids:

• Non-metals do not react with acids to form hydrogen gas .it is because non-metals do not give electrons to reduce hydrogen ions ( H⁺ ) of acids into hydrogen gas.

Reaction With Salt Solution:

• A more reactive non-metal displaces a less reactive  non-metal from its salt solution. 

e.g

2 NaBr (aq) + Cl₂ (g)  → 2 NaCl  (aq)  + Br₂ (aq)

• Chlorine is more reactive than Bromine, so chlorine displaces bromine from sodium bromide to form sodium chloride solution.

Reaction With Chlorine:

• Non-metals react with chlorine to form covalent chloride.

• These are usually liquids or gases

H₂ (g) + Cl₂ (g) → 2HCl (g)

P₄ + 6Cl₂ (g)  → 4 PCl₃ (l)

Reaction With Hydrogen:

• Non-metals react with hydrogen to form covalent hydrides. Hydrides exist in liquid or gaseous state.

H₂ (g) + S (s) →  H₂S (g)

Hydrogen sulphide  ( H₂S )  has a  smell  like  rotten egg.

H₂ (g) +3 N₂ (g) → 2NH₃ (g)

2H₂ (g) + O₂ (g) → 2H₂O(l)

USES OF NON-METALS :

Hydrogen:

• Hydrogen is used in the hydrogenation of vegetable oils to make vegetable ghee. 
• Hydrogen is used in the manufacture of ammonia (whose compounds are used as fertilisers).   
• Liquid hydrogen is used as a rocket fuel.

Carbon:

• Carbon (in the form of graphite) is used for making the electrodes of electrolytic cells and dry cells.

Nitrogen:

• Nitrogen is used in the manufacture of ammonia, nitric acid and fertilizers. .

• Due to its inertness, nitrogen is used to preserve food materials.

• Compounds of nitrogen like Tri Nitro Toluene (TNT) and nitroglycerine are used as explosives.

Sulphur:

• Sulphur is used for manufacturing sulphuric acid. 
• Sulphur is used as a fungicide and in making gun powder 
• Sulphur is used in the vulcanisation of rubber.