Answser: the representative unit of carbon dioxide is the molecule CO₂.
Justification:
1) carbon dioxide is made of one atom of carbon and two atoms of oxygen chemically bonded by covalent bonds.
2) A molecule is formed when two or more atoms are bonded by covalent bonds.
3) Some other examples of molecules are: water (H₂O), oxygen (O₂), the fats, the carbohydrates, glucose.
4) The term molecule is reserved for atoms bonded by covalent bonds, so ionic compounds like NaCl, are not named molecules. NaCl is told to represent a formula unit instead of a molecule.
