* Elemental molecules: These are molecules composed of atoms of the same element. For example, oxygen gas (O2) and nitrogen gas (N2) are elemental molecules.
* Covalent molecules: These are molecules composed of atoms of different elements that are held together by covalent bonds. For example, water (H2O) and carbon dioxide (CO2) are covalent molecules.
* Ionic molecules: These are molecules composed of atoms of different elements that are held together by ionic bonds. For example, sodium chloride (NaCl) and potassium iodide (KI) are ionic molecules.
* Metallic molecules: These are molecules composed of atoms of metals that are held together by metallic bonds. For example, copper (Cu) and aluminum (Al) are metallic molecules.
* Polymers: These are molecules composed of long chains of repeating units. For example, polyethylene and polypropylene are polymers.
The specific molecules present in a small amount of compound will depend on the chemical composition of the compound.
