Question

What are atom and molecules

Answer 1

atoms are the smallest unit of matter
molecules-two or more atoms join together to form molecules

Answer 2

Atom is the smallest unit, which is neither be created nor be destroyed.
But, nowadays, Uranium is split-ted to give energy.
Molecules are the group of atoms.
For example, Oxygen is an atom.
But, O₂ is a molecule.

Thank you.
Hope this will help you.