NCERT 9th Class (CBSE) Science: Atoms and Molecules Quiz
20 Multiple Choice Questions related to NCERT 9th Class (CBSE) Science: Atoms and Molecules Quiz:
- In a chemical substance the elements are always present in definite proportions by mass.
E.g., In water, the ratio of the mass of hydrogen to the mass of oxygen H : O is always 1:8
- The smallest particle of matter, which can take part in a chemical reaction is called atom.
- The smallest particle of an element or compound which can exist independently is called molecule.
- The number of atoms constituting a molecule is known as its atomicity.
- John Dalton coined the term atom.