Chemical Properties Of Metals And Non-Metals

Key Notes :

Chemical Properties of Metals & Non-Metals1. Reaction of Metals with Oxygen

Metals form their oxides when reacting with oxygen.
Metal + oxygen → Metal oxide
Metal oxides are basic in nature.
Example:

• Reaction of Iron metal with oxygen:
  When iron reacts with moist air, it forms rust. Rust is iron oxide. Articles made of iron, such as grills, fencing, etc. are getting rusted because of the reaction with moist air.

• Rust is reddish-brown in colour and is iron oxide. Iron oxide is basic in nature. It turns red litmus blue.
• Reaction of Magnesium metal with oxygen:
  When magnesium is burnt in the air, it forms magnesium oxide. Burning in the air means reacting with oxygen.
  Magnesium (Mg) + Oxygen (O₂) → MgO (Magnesium oxide)
  Magnesium oxide forms magnesium hydroxide with water. Solution of Magnesium oxide turns red litmus paper blue. This means magnesium oxide is basic in nature.

2. Reaction of Non-Metals with Oxygen

Non-metals forms their oxides when reacting with oxygen.

Thus, Non-metal forms their oxide when reacts with oxygen.

Non-metal oxides are acidic in nature.

• Reaction of sulphur with oxygen:
  When sulphur is burnt in the air, it forms sulphur dioxide.
  The solution of sulphur dioxide turns blue litmus paper red. Sulphur dioxide forms sulphurous acid when dissolved in water. Thus, sulphur dioxide is basic in nature.
• Reaction of carbon with oxygen:
  When carbon is burnt in the air, it forms carbon dioxide. You can observe that when coal (carbon) is burnt it forms smoke, which contains carbon dioxide.
  Carbon dioxide is acidic in nature. The solution of carbon dioxide in water turns blue litmus paper red.
  

3. Reaction with Water

Generally, metals form respective hydroxides when they react with water. Some metals react vigorously with water like in the case of sodium. It is stored in kerosene. While some metals reacts very slowly with water like in the case of iron.

• Reaction of sodium metal with water:
  Sodium metal vigorously reacts with water and forms sodium hydroxide along with a lot of heat.
• 

• Reaction of potassium with water:
  Potassium metal vigorously reacts with water and forms potassium hydroxide along with a lot of heat.
  
  For Non-metals:
  Non-metals generally do not react with water. Rather some non-metals that react with air vigorously are stored in water.

4. Reaction with Acid

Metals give hydrogen gas when they react with dilute acid.

• Reaction of zinc with dilute acid:
  Zinc gives hydrogen gas along with zinc chloride when it reacts with hydrochloric acid.
  Similarly, zinc gives hydrogen gas along with zinc sulphate when it reacts with sulphuric acid.
  
  This method is used to produce hydrogen gas in laboratory.
• Reaction of sodium metal with dilute acid:
  Sodium gives hydrogen gas and sodium chloride when reacts with dilute hydrochloric acid (HCl).
  
• The reaction of Aluminium with dilute acid:
  Aluminium gives hydrogen gas along with aluminium chloride when it reacts with dilute hydrochloric acid.
  
  Copper does not react with dilute sulphuric acid even on heating, but it reacts with concentrated sulphuric acid. Copper, silver and gold are considered noble metals as do not react with dilute acid.
  For Non-Metals: Generally, non-metals do not react with dilute acid.

5. Reaction with Base

Metals give hydrogen gas when they react with a base.

• Reaction of aluminium metal with sodium hydroxide:
  Aluminum metal forms hydrogen gas and sodium aluminate when it reacts with sodium hydroxide.
  
  Similarly, zinc gives sodium zincate and hydrogen gas when it reacts with sodium hydroxide.

What is Displacement Reaction?

During reaction , if a metal replaces another metal from its compound then such reactions are called displacement reaction.

Metals can actually be arranged as per their reactivity order, thus, a more reactive metal will always displace a less reactive metal from its compound but a less reactive one cannot replace a more reactive metal.

In the above equation, metal A is more reactive than metal B.

Example:

• When aluminium metal is dipped in the solution of copper sulphate, it forms aluminium sulphate and copper.
  
•  When iron reacts with a solution of copper sulphate, it gives iron sulphate and copper.

In the above two reactions, aluminium and iron are more reactive than copper, that’s why they replace copper from the solution of copper sulphate.

When copper metal is dipped in the solution of aluminium nitrate, no reaction takes place. Because copper is less reactive than aluminium.

Try yourself: The most reactive metal is a.Sodium b.Lithium c.PotassiumCorrect Answer d.Calcium

Explanation

Potassium is more reactive than Sodium and Lithium because Potassium is bigger than them. So, the outermost electron is farther away from nucleus. So the ionization energy in K is less than that in Na or in Li. So, Potassium is more reactive than many other metals.

Let’s practice!