Classification of matter into these three states of solid, liquid, and gas is easy to find in our surroundings. These are naturally distinct in our environment, such as water which universally represents itself as a splendid example in solid, liquid, and gaseous state. These three states of matter are usually found in normal temperature and pressure situations. Whereas, in extreme situations, some other states of matter can be found. Recently there has been the discovery of Plasma, Bose-Einstein state, and neutron stars extending the classification of matter systems. Some quark plasma states are also included in the list and are believed to be possible to exist.

Classification of the matter:

States of matter are considered as one of the most interesting topics of the chemical universe. We will now get a detailed analysis of solid-liquid and gaseous states along with their peculiar physical and chemical properties. We will also get to know about their examples and interconverting phenomenon and facts.

1. Solid State:

Definition:

• Matter whose molecules are closely packed with each other due to strong molecular force, constitutes the solid-state and solids.

Identifying characteristic of these solids are:

• Definite shape, size, and volume:

Since the molecules are tightly bound with each other, the particles can’t exhibit rigid shape, size and volume.

• Melting point and Boiling point:

They have high melting and boiling point because of the strong intermolecular force of attraction between the molecules.

Classification of solids:

Solids generally exhibit peculiar characteristics that set them apart from liquids and gases. Based on their nature of arrangement of molecules and patterns they are further classified as Crystalline and amorphous Solids.

• Crystalline Solids:

Definition:

• Solids with typical geometry and definite arrangements of molecules are called Crystalline solids.

Characteristics:

• They have sharp melting and boiling points.
• The molecules are arranged in long order as per 3-dimensional network.
• They show cleavage property when they are cut through a knife or blade.
• They have a definite heat of fusion.
• These are also called true solids.

Examples:

• Sodium chloride
• Quartz
• Diamond
• Amorphous Solids:

Definition:

• Solids with no definite geometry and molecular arrangement represent the amorphous solids.

Characteristics:

• They get softened after an extent of compressibility.

• Molecules are not arranged in a three-dimensional network.
• These are also called Pseudo solids.
• They have an irregular shape and, when cut does not follow the symmetrical cleavage property.
• These solids do not have definite heat of fusion.

Examples:

• Glass
• Rubber
• Plastic

Inter conversions:

• A solid can be converted to a liquid by the process of melting.
• Liquid can be converted to solid by the process of freezing.
• A solid can also be converted directly to gas by the process of sublimation.

2. Liquids:

Definition:

• Matter whose shape and size can change but volume remains the constant constitute the liquid types of matter.

Identifying Characteristics:

• In liquids molecules have molecular interactions, greater than gaseous state and lesser than solid-state.
• Here the thermal energy is more than the solid-state and lesser than the gaseous state.
• The intermolecular distance is slightly more than solids but less than gases.
• Usually the volume is constant, but a small change in volume occurs when a solid converts to liquid.
• Liquids have a nonrigid structure due to continuous breaking and building of bonds between the molecules, but they have definite interactive energy.

Inter conversions:

• Liquids can be converted to solid by the process of freezing.
• Liquids can be converted to gases by the process of evaporation. 

3.  Gases:

Definitions:

• Matter which has no definite shape, size, and volume constitutes the gaseous state.

Identifying characteristics:

• In gases molecules have almost no molecular force of interactions, least among the list of solid and gases.
• Random thermal motion exists which allows free translatory movements of molecules.
• Hence, they don’t exhibit rigid shape, size, and volume because they have large intermolecular space between the particles.
• Also, they have a low intermolecular force of attraction and high intermolecular force of repulsion.
• As a result, gases are highly compressible due to the largely empty space between them.

Interconversions:

• Gases can be converted into a liquid by the process of condensation.
• Solid can be converted into gas by the process of sublimation.

4.  Plasma:

• Plasma is superheated matter, where the excited electrons get ripped away from the atoms forming an ionised gaseous state.
• It is generally called the fourth major state of matter.
• It is neither solid nor liquid, it is actually a substate of gases with no fixed shape, size, and volume.

Conclusion:

The matter is the collection of atoms or molecules with different arrangement patterns, depicting different physical and chemical properties. Based on these properties they are divided as Solids, Liquids, and gaseous states of matter. Interestingly these states of matter are interconvertible in nature and characteristics.