Question

Difference between atom and molecule class 9\

Answer 1

Atom:Atom is a smallest part of matter while as
Molecule:Molecule is a smallest unit of matter.

Answer 2

Hy friend here is your answer.
Atom: The smallest particles of an element is called atom. Which takes part in chemical reaction and which has all the properties of the elements.
Molecules:The smallest particles of a substance which is found in free states but does not take part in a chemical and which has all the properties of the substance.