Write the chemical formulae of the following.

(a) Magnesium Chloride

(b) Calcium Oxide

(c) Copper Nitrate

(d) Aluminium Chloride

(e) Calcium Carbonate.

 

Answer

(a) Magnesium Chloride

It contains 2 elements Magnesium(Mg) and Chlorine(Cl)

 

Valency of Magnesium (Mg) is 2

Valency of Chlorine (Cl) is 1

 

These valencies interchange while writing formula as shown below

Hence, the formula becomes MgCl 2

 

(b) Calcium Oxide

It contains 2 elements Calcium(Ca) and Oxygen(O)

 

Valency of Calcium (Ca) is 2

Valency of Oxygen (O) is 2

 

These valencies interchange while writing formula as shown below

Hence, the formula becomes CaO

 

(c) Copper Nitrate

It contains 2 elements Copper(Cu) and Nitrate(NO 3 )

 

Valency of Copper(Cu) is 2

Valency of Nitrate(NO 3 ) is 1

 

These valencies interchange while writing formula as shown below

Hence, the formula becomes Cu(NO 3 ) 2

 

(d) Aluminium Chloride

It contains 2 elements Aluminium(Al) and Chlorine(Cl)

 

Valency of Aluminum (Al) is 3

Valency of Chlorine (Cl) is 1

 

These valencies interchange while writing formula as shown below

Hence, the formula becomes AlCl 3



(e) Calcium Carbonate

It contains 2 elements Calcium(Ca) and Carbonate(CO 3 )

 

Valency of Calcium (Ca) is 2

Valency of Chlorine (CO 3 ) is 2

 

These valencies interchange while writing formula as shown below

Hence, the formula becomes CaCO 3

  1. Class 9
  2. Chapter 3 Class 9 - Atoms And Molecules (Term 2)

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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