General Introduction to the Solid State

As you know there are three states of matter – solids, liquids, and gases. Most objects around us are in their solid state. Everything from the chair you are seated on to the sand on the beach is solid. However, their physical appearances can vary their physical properties are similar. Let us learn a bit more.

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Solid State

As we have studied before we can change the physical properties of an object or element by varying its temperature and pressure, This phenomenon is known as Change of State. For example when we heat water to turn it into water vapor or freeze it to turn it into ice.

The states of matter and its stability actually depends on two opposing forces found in the atom of an element. These are the two forces responsible for the formation and stability of a solid. Let us discuss these two forces in some detail.

• Intermolecular Forces: Intermolecular forces exist between molecules of an element. They actually determine not only the state of the matter but also factors such as boiling point, melting point, enthalpy of the elements. They keep the atoms or molecules of matter close together in a bond.
• Thermal Energy: Thermal energy is a form of kinetic energy. It is the energy that particles possess due to their motion. It is the internal energy of an object that is responsible for its temperature. Transfer of thermal energy happens through the transfer of heat. With a rise in the thermal energy, the particles of matter tend to move faster and vice-versa.

These two forces keep the atoms of solids closely packed in a fixed structure we call a lattice. At low temperatures the thermal energy of particles of solid matter is low. So the movement of particles is minimal, the intermolecular force is high and spaces between atoms is very less. This gives solid their basic properties.

Browse more Topics under The Solid State

• Crystalline and Amorphous Solids
• Space Lattice or Crystal Lattice and Unit Cell
• Number of Particles in Unit Cells
• Close Packing in Crystals
• Tetrahedral and Octahedral Voids
• Radius Ratio Rules
• Density of a Cubic Crystal
• Imperfections or Defects in a Solid
• Electrical Properties of Solids
• Magnetic Properties of Solids

General Characteristics of Solids

Now if you actually observe all the solid objects around you, you will notice many dissimilarities between them. Their shapes, texture, weight, size, colors etc may vary greatly. But there are a few physical properties of a solid that holds true for all solids baring a few rare exceptions. Let us take a look at few such common/general characteristics of solids.

• Definite Mass and Volume and Shape: Mass and Volume of a solid and liquids remain same. But unlike liquids solids also have a fixed shape. The tightly packed atoms of a solid ensure that they maintain a definite shape.
• Strong Intermolecular Forces: The tight close knit packing of molecules is due to the strong intramolecular forces between particles. This also means that the intermolecular distances between particles are also very small/short. This is the reason why solids hold their shape and do not spread out like liquids or gasses.
• Solids are Incompressible: As there is already no spaces between molecules, solids cannot be compressed further
• Boiling Points: Solids have Boiling and Melting Points above room temperature
• Thermal Energy: Solids have low thermal energy. So this means their constituent particles do not roam about freely like in liquids and gases. They only oscillate about their mean positions.

Solved Question for You

Q: Which states of matter have no miscibility?

1. Solid
2. Gases
3. Liquids
4. All of the above

Ans: The correct answer is “A”. Solids do not mix with each other. This is because they have very little space between their atoms since these atoms are tightly packed in solids.