CBSE Class 10 Answered

An atom is the smallest particle of the element that can exist independently and retain all its chemical properties

A molecule is the smallest particle of an element or a compound capable of independent existence under ordinary conditions

The mole is the amount of substance that contains the same  number of particles (atoms/ ions/ molecules/ formula units etc.) as there are atoms in exactly 12 g of carbon-12

Atomic mass is mass equal to 1/12 th the mass of an atom of carbon-12.Atomic weight and  atomic mass are used synonymously

The molecular mass of a substance is the sum of the atomic masses of all the atoms in a molecule of the
substance. Molecular weight and  molecular mass are used synonymously

First know what atoms,molecules, atomic and molecular mass and mole concept. After that try solving the question, it will help