Question

What is the difference between atoms, elements, molecules and compounds?

Answer 1

Atoms	Elements	Molecules	Compounds
Atom is the smallest indivisible part of matter which retains its identity.	An element is a pure substance which is made up of only one kind of atoms.	A molecule is a pure substance which is either made up of only one kind or more than one kind of atoms.	When two different types of atoms combine to form a molecule, the pure substance formed by these molecules will be called a compound.
Example: Oxygen(O) atom	Example: Aluminium(Al)	Example: Oxygen(O2) molecule	Example: Water (H2O) molecule