Elements are composed of atoms and compounds are composed of?

Elements are atoms, atoms are elements. Elements are not larger objects made up of smaller things (atoms). Elements are specific species' atoms, which have a specific Atomic Mass which gives rise to the characteristics of the element. Compounds are composed of elements.

It is important to note the difference between a compound and a molecule; the Words, although often used interchangeably, have aspecific meaning in chemistry. A molecule is a certain type of compound in which the elements have bonded covalently. As such, all compounds are not molecules, but all molecules are compounds.