* Molecule: A molecule is a group of atoms that are chemically bonded together. In other words, a molecule is a neutral group of atoms that are held together by covalent chemical bonds. Molecules can be made up of atoms of the same element (e.g., O2, N2, H2) or different elements (e.g., H2O, CO2).
* Elemental substance: An elemental substance is a substance that is made up of only one type of atom. For example, iron (Fe), gold (Au), and helium (He) are all elemental substances.
In summary, a molecule is a group of atoms that are chemically bonded together, while an elemental substance is a substance that is made up of only one type of atom. Therefore, a molecule cannot also be an elemental substance.
