All matter around us is made up of tiny particles called atoms and molecules. Based on composition, matter can be classified into elements, compounds, and mixtures. An element is a pure substance made up of only one kind of atom, such as oxygen, iron, or gold. A compound is formed when two or more elements combine chemically in a fixed proportion, like water (H₂O) or carbon dioxide (CO₂). The properties of a compound are usually very different from the properties of the elements that form it.
A mixture, on the other hand, is made up of two or more substances that are physically combined and can be separated by physical methods. Mixtures may be homogeneous (uniform, e.g., salt dissolved in water, air) or heterogeneous (non-uniform, e.g., sand in water, oil in water). Unlike compounds, the components of a mixture retain their individual properties and do not combine in a fixed ratio. Alloys like brass and steel are special types of mixtures called solid solutions. This classification of matter helps us understand its nature and how different materials can be used in daily life.
