Question

How do you determine the difference between an element and a compound?

Answer 1

Answer:  An element is a single atom.

Explanation:

An element cannot be divided into smaller parts (that was true before the physicists built atomic weapons and the Large Hadron Collider).  But the definition of an atom was establish before Einstein, Oppenheimer, and Rutherford.  An element is an atom.  A compound is two or more atoms bonded together.   Carbon is an element, and one carbon all by itself is an atom.  A carbon that has some hydrogens attached (e.g, methane, CH4) are compounds.  An oxygen atom is just sa single O.  We write O2 since that is the form it takes in nature.  O is an atom, O2 is a molecule.