What is the difference between an atom and a molecule?

An atom is the basic unit of matter and consists of protons, neutrons, and electrons. It represents the smallest unit of an element that retains the properties of that element. On the other hand, a molecule is formed when two or more atoms chemically bond together. This bonding can involve the same type of atoms, as in diatomic molecules like oxygen (O2), or different types of atoms, as in water (H2O).

Understanding that a molecule is composed of multiple atoms highlights the structural and functional differences between the two. Molecules can become quite complex, creating various substances with diverse properties and behaviors, which would not be possible if we considered single atoms only. This distinction is critical in fields such as chemistry and biology, where the interactions and functions of different molecules within biological systems are central to understanding processes like metabolism, signaling, and structural functions in organisms.