Anything that has mass and occupies space is called matter. A matter is made up of tiny particles. These particles are invisible to the naked eye.
Classification of matter
Based on the intermolecular forces of attraction and spacings between the particles matter is broadly classified into three categories:
The solid-state is one of the fundamental states of matter. Solids differ from liquids and gases by the characteristic of rigidity. The molecules of solids are tightly packed because of strong intermolecular forces; they only oscillate about their mean positions. Whereas, liquids and gases possess the property of fluidity and can easily flow. Solids are described as a state of matter with a rigid structure and a distinct shape and volume. Solids are the least compressible and have the least thermal expansion.
Examples – Book, Iron
Due to weak intermolecular interactions, the molecules in a liquid are packed tightly together. These forces are less powerful than those of solids, but more powerful than those of gases. Liquids have a lot of space between their molecules, which makes them easier to flow. Liquids have a fixed volume and can easily take on the shape of a vessel. When we raise the temperature of solids to the point where they begin to melt, we are converting them to liquids. Liquids have a density that is somewhere between that of solids and gases. Liquids have slightly higher compressibility and thermal expansion than solids.
Example – Water
The distances between the molecules are huge in this state of matter (intermolecular distance is in the range of 10−7–10−5cm). The intermolecular forces between them are negligible. As a result, translational, rotatory, and vibratory motions are dominant in gases. Gases don’t have a defined volume or shape. They’re also very compressible and have a lot of thermal expansion.
Example – Oxygen