* Molecules: These are groups of two or more atoms held together by chemical bonds. They are found in many solids, especially those formed from covalent bonding. Examples include water (H₂O) in ice or sugar (C₁₂H₂₂O₁₁).
* Particles: This is a broader term that can refer to atoms, ions, or molecules. So, solids made of metals (like iron), ionic compounds (like salt), or network solids (like diamond) have particles, but not necessarily molecules.
In essence, all solids are made of particles, but some solids are made of molecules.
