What is the basic unit of matter?

The correct answer is the atom because it is defined as the smallest unit of matter that retains all the chemical properties of an element. Atoms consist of subatomic particles: protons, neutrons, and electrons. They combine in various ways to form molecules and compounds, but on their own, atoms are the fundamental building blocks of everything in the universe.

Elements are pure substances composed of only one type of atom, and while they are foundational in chemistry, they are not the smallest units of matter. Molecules are formed when two or more atoms bond together, representing a combination rather than the basic unit. Compounds consist of two or more different types of atoms chemically combined, which again are formed from atoms but are not themselves the basic units of matter.

Understanding that atoms are the building blocks helps clarify their role in forming the various substances and materials we encounter in both science and everyday life.