What term describes the smallest unit of matter that cannot be broken down by chemical means?

• A. Molecule
• B. Atom
• C. Element
• D. Compound

Answer: (B)

Atoms are the fundamental building blocks of matter. They are the smallest unit that retains the properties of an element, and chemical changes work by breaking or forming bonds between atoms or by rearranging how electrons are shared. Because chemical processes deal with atoms and their bonds, you can’t break an atom apart using chemical means—only nuclear processes can do that.

Molecules, on the other hand, are bonds between two or more atoms; you can break them into smaller molecules or into individual atoms through chemical reactions. An element is a substance made of just one type of atom, whereas a compound is made from two or more elements bonded together in a fixed ratio, often existing as molecules.

So the term that describes the smallest unit of matter that cannot be broken down by chemical means is atom.