Chemical properties of non-metals

• There are generally 5, 6 or 7 electrons in the outermost shell of non-metals. Their molecules are usually polyatomic in the gaseous state.
• They generally form acidic oxides.
• They form anions (negative ions) by gaining electrons to complete their octet.
• Non-metals are known as oxidizing agents because they ionize by gain of electrons.

REACTION OF NON METALS

REACTION OF NON-METALS WITH OXYGEN

• Non- metals react with oxygen to form acidic oxides or neutral oxides.
• For example: Carbon forms an acidic oxide CO₂, sulphur forms an acidic oxide SO₂, and hydrogen forms a neutral oxide, H₂
• The non-metal oxides are covalent in natures which are formed by the sharing of electrons.
• The acidic oxides of non-metals dissolve in water to form acids. The acidic oxides of non-metals turn blue litmus solution to red.
• Example: Carbon is a non-metal. When carbon burns in air it reacts with the oxygen of the air to form an acidic oxide called carbon dioxide:

• Example: Sodium metal reacts with the oxygen of air at room temperature to form a basic oxide called sodium oxide:

REACTION OF NON-METALS WITH WATER

• Non-metals do not react with water (or steam) to evolve hydrogen gas, as, non-metals give electrons to reduce the hydrogen ions of water into hydrogen gas.

REACTION OF NON-METALS WITH DILUTE ACIDS

• Non-metals do not react with dilute acids.

REACTION OF NON-METALS WITH SALT SOLUTIONS

• While reacting with salt solutions, the more reactive non-metal displaces a less reactive non-metal from its salt solution.
• The passing of chlorine in a solution of sodium bromide gives sodium chloride and bromine.