We have seen that, 

Some metals react immediately and vigorously with reactants, while others react slowly , or when the reaction mixture is heated/catalysed. Some do not react at all. 

 

Metals react based on their reactivity.  

Reactivity is the tendency of chemical substances to form products by itself .

 

  • Reactivity series is an arrangement of metals and non-metals based on their tendencies to react with certain tendencies. 
  • The elements are arranged in decreasing order of their reactivity .

Reactivity series-01.jpg

  • The arrangement of metals in a vertical column in the degree of their decreasing reactivities (quality of being reactive) is called the reactivity series of metals.
  • The most reactive metal is placed at the top whereas the least reactive metal is placed at the bottom .




  • Sodium and Potassium can react vigorously with oxygen, water, and acids, as soon as they come into contact with them.
  • On the other hand, heat is required for the reaction of magnesium with oxygen or air, or the reaction of magnesium with water. 
  • Thus, we can say that magnesium is less reactive than Sodium or Potassium.
  • Similarly, we can say that Silver, Mercury, Gold, and Platinum are the least reactive metals as they rarely react with chemicals without external help. 

 

Metal/Reactant

Oxygen

Water

HCl

H2SO4

HNO3

Potassium

Reacts vigorously, catches fire

Reacts vigorously with cold water, catches fire

Reacts violently to form KCl

Reacts violently to form K2SO4

Reacts violently to form KNO3

Sodium

Reacts vigorously, catches fire

Reacts vigorously with cold water, catches fire

Reacts violently to form NaCl

Reacts violently to form Na2SO4

Reacts violently to form NaNO3

Calcium

Reacts with Oxygen to form oxide. Produces heat.

Reacts with cold water, produces some heat

Reacts rapidly to form CaCl

Reacts rapidly to form CaSO4

Reacts rapidly to form Ca(NO3)2

Magnesium

Requires external heat/combustion to react

Requires external heat/hot water to react

Reacts rapidly to form MgCl2

Reacts rapidly to form MgSO4

Reacts rapidly to form Mg(NO3)2

Aluminium

Requires external heat/combustion to react

Requires high amount external heat/steam to react

Reacts slowly to form AlCl3

Reacts slowly to form Al2(SO4)3

Reacts slowly to form Al(NO3)3

Zinc

Reacts only on strong heating

Requires high amount external heat/steam to react

Reacts slowly to form ZnCl2

Reacts slowly to form ZnSO4

Reacts slowly to form Zn(NO3)2

Iron

Reacts only on strong heating/prolonged exposure

Requires high amount external heat/steam to react

Reacts very slowly to form FeCl2

Reacts slowly to form FeSO4

Reacts slowly to form Fe(NO3)3

Tin

Reacts only on strong heating/prolonged exposure

Reacts with steam to form SnO2+H2

Reacts very slowly to form SnCl4

Reacts slowly to form SnSO4

Reacts slowly to form Sn(NO3)4

Lead

Reacts only on strong heating/prolonged exposure

Reacts with steam to form PbO2+H2

Reacts very slowly to form PbCl4

Reacts slowly to form PbSO4

Reacts slowly to form Pb(NO3)2

Hydrogen

-

-

-

-

-

Copper

Reacts only on strong heating/prolonged exposure

Does not react with Water

Does not react with acid

Reacts with hot, conc. acid to form CuSO4

Reacts slowly to form Cu(NO3)2

Mercury

Does not react with Oxygen

Does not react with Water

Does not react with acid

Reacts with hot, conc. acid to form Hg2SO4

Reacts slowly to form Hg2(NO3)2

Silver

Does not react with Oxygen

Does not react with Water

Does not react with acid

Reacts with hot, conc. acid to form Ag2SO4

Reacts slowly to form Ag(NO3)

Gold

Does not react with Oxygen

Does not react with Water

Does not react with acid

Does not react with acid

Does not react with acid

Platinum

Does not react with Oxygen

Does not react with Water

Does not react with acid

Does not react with acid

Does not react with acid





Role of hydrogen in determining the reactivity series

In displacement reactions, a more reactive element displaces a less reactive element.

  • If a metal is above Hydrogen in the reactivity series, then it will displace hydrogen from water and acids, and hence produce hydrogen gas in the reaction.
  • These lose electrons more readily than hydrogen, reactions with other substances are faster .
  • Metals like Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Tin and Lead are more reactive than hydrogen.

 

  • Similarly, if a metal is below Hydrogen in the reactivity series, then it cannot displace hydrogen from water and acids, and thus, will not produce hydrogen gas upon reaction with water and acids.
  • These lose electrons less readily than hydrogen, thus it reacts slowly with other substances.
  • Metals like Gold, Silver, Copper and Mercury are less reactive than hydrogen and hence do not displace hydrogen from its salts/solutions.





Reaction of Metals with Other Metal Salts

 

What is a metal salt? 

  • A metal salt is a compound formed when Hydrogen of an acid is replaced by a metal .

For Example : 

  • In Zinc Sulphate, Zinc is a metal and Sulphuric Acid is an acid. Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas.

Zn (s) + H 2 SO 4 (aq) ---> ZnSO 4 (aq)+ H 2 (g)

  • This Zinc Sulphate is a Metal Salt , as it is formed by replacement of Hydrogen from H2SO 4  to form ZnSO 4 .

 

What is a Solution of Metal Salt?

  • It is a mixture of Metal Salt in water .
  • Example : Zinc Sulphate (ZnSO 4 )  is a metal salt. But Zinc Sulphate (ZnSO 4 ) (aq) is a solution of metal salt.

Fig. ) Zinc Sulphate salt                    Zinc Sulphate (aq)

Displacement Reactions :

When a more reactive metal is placed in a salt solution of a less reactive metal, the more reactive metal displaces the less reactive metal from its salt solution and forms a salt solution via displacement reaction.

 

Here, Metal A is more reactive than Metal B. Thus, it pushes metal B out of its salt solution.



For example : Zinc placed in Copper sulphate solution.

  • We know that Zinc is more reactive than Copper (refer: reactivity series)
  • When we put a piece of zinc metal in a copper sulphate solution, 
  • The zinc metal, being more reactive, displaces copper from the copper sulphate and forms zinc sulphate.  
  • This is called a displacement reaction.
  • However if we put a piece of copper metal in a zinc sulphate solution, no displacement takes place 
  • This is because copper is less reactive than zinc.

 

  1. Class 10
  2. Chapter 3 Class 10 - Metals and Non-Metals (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo