What is matter primarily made of?

Matter is primarily made of atoms, which are the basic building blocks of all matter. Atoms combine in various ways to form molecules and compounds, but at the most fundamental level, everything around us is constructed from atoms. Each element on the periodic table is defined by the type and number of atoms it contains. For example, a water molecule consists of two hydrogen atoms and one oxygen atom, but those atoms themselves are the essential units that contribute to the existence of all substances. Thus, understanding that matter is fundamentally composed of atoms provides a foundational perspective in chemistry and physics.