Question

what is relationship between atoms and cells of body

Answer 1

Atom: It's tiniest fundamental particle which makes up all known matter in the entire known universe. Everything that you see, smell, breathe, touch, eat is made up of atoms.

Cells : Cells are the fundamental living, functional and structural unit of a living organism. Cells are made of various proteins, lipids, carbohydrates and other compound essential for life. These are called biomolecules and are made up ofATOMS. 
Cells of same structure, origin and function come together to form  a tissue which forms an organ which forms an organ system and finally it forms an organism. 

Answer 2

A cell is made of molecules and a molecule is made of atoms. that a simplest way of putting it.More complicated is that a cell is made up of macromolecules.such as proteins, lipids etc.A molecule is a particular configuration of atoms.