Final answer:
An element is a pure substance consisting of one type of atom, a molecule is a unit of two or more atoms bonded together, and a compound is a pure substance made up of atoms of different elements.
Step-by-step explanation:
An element is a pure substance consisting of only one type of atom. An example of an element is oxygen, which is made up of only oxygen atoms.
A molecule is a unit of two or more atoms bonded together. For example, water (H2O) is a molecule consisting of two hydrogen atoms bonded to one oxygen atom.
A compound is a pure substance that is made up of atoms of different elements. An example of a compound is sodium chloride (NaCl), which is made up of sodium and chlorine atoms.
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