4th Class Science Matter and Materials Molecules


Category : 4th Class

*     Molecules


A smallest particle of matter, which can exist in a free state is called a molecule. Structure of molecules of some elements has been given below.


Molecules of any given substance are all similar. A molecule is defined as a group of at least two atoms in a definite arrangement. Molecules are formed by the combination of two or more atoms. The Properties of a substance are the properties of its molecule. Molecules can be subdivided to individual atoms. The atoms are bounded together in a molecule. Molecules also are not visible to the naked eye. It can be seen through highly magnifying microscopes and other scientific devices.




Water is comprised of numerous water molecules. Each water molecule is made up of one oxygen atom and two hydrogen atoms. So a water molecule can be further divided into oxygen and hydrogen atoms.


 Hydrogen           Oxygen                 Water

Schematic Representation of Water Molecule  

Group of atoms in a definite arrangement to form molecule    





    Consider the statements given below and select the right answer.

Statement A: A molecule is defined as a group of at least two atoms.

Statement B: Molecules are visible to the naked eye.

(a) Statement: A is true

(b) Statement: B is true

(c) Both Statement: A and B partly true (d) Both Statement: A and B are partly false

(e) None of these


Answer: (a)



     Molecules of water is made of which one of the following kind of atoms?

(a) Helium and Oxygen

(b) Nitrogen only

(c) Carbon and Hydrogen

(d) Oxygen and Hydrogen

(e) None of these


Answer: (d)

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