Example: diamond (a hard, poor conductor of electricity and heat) and graphite (a soft and good electricity and heat conductor). Covalent solids: Also called network solids, they have non-metallic covalent bonds.Metallic solids: Cations of metals are held together by kernels, which is the sea of valence electrons.H-bonded molecular solids have polar hydrogen bonds with electronegative elements.Non-polar solids are insulators with low melting points in which constituents have non-polar covalent bonds.They are mostly gases or liquids at room temperature. Polar solids constituents have polar bonds and strong dipole-dipole interactions.Molecular solids: They are categorised into polar, non-polar, and H-bonded molecular solids.They are hard, brittle, and conduct electricity in a molten and aqueous state. Ionic crystalline solids: The constituent particles are ions.The classification of crystalline solids can be done into four types based on the nature of chemical bonding: Therefore, these solids are also called supercooled liquids.Īmorphous solids are isotropic in nature, i.e., the value of any physical property does not change as we change the direction due to the unordered arrangement of constituent particles. To get an amorphous solid, we solidify the liquid very rapidly. The intermolecular forces between constituent particles are not identical, i.e., the distance between two particles may vary. They lack geometry, and upon breaking, they form fragments with no defined surfaces. Amorphous solids, by their very name, are the ones that do not have a regular arrangement of constituent particles. The term ‘amorphous’ means irregular or shapeless. Amorphous Solids or Supercooled Liquids.Crystalline solids are anisotropic and have a sharp melting point. They have highly defined faces and edges. The particles are assembled in a highly-ordered manner, i.e., they exhibit long-range order. A repeating unit (known as a unit cell) repeats in all directions to give a solid its 3-D structure. When the particles of a solid are arranged in a definite pattern such that they have a repeating pattern, they are said to form crystalline solids. Solid-state compounds can be categorised into two types based on the arrangement of constituent particles: On application of force, they can break into several pieces, but their shape does not change.High density (This is not true for water, wherein the density of ice is lower than liquid water).The following general characteristics of solid state apply to matter: Hence, its effect is somewhat opposite to that of intermolecular forces. The higher is the thermal energy, the farther away the particles would be. Thus, they vibrate more vigorously at their positions. When temperature increases, more heat is transferred from the environment to molecules. It depends on the surrounding temperature. Thermal Energy: It is a form of energy that the particles possess by virtue of their kinetic movement.One of the general characteristics of the solid state of matter is high intermolecular forces of attraction, due to which the particles are close together. The higher the intermolecular forces of attraction, the closer in distance the molecules would be, i.e., they would be more densely packed. Intermolecular Forces: The forces of interaction between two molecules in a given state of matter are known as the intermolecular forces of attraction.The matter’s stability in a given state depends on the following two factors: Similarly, every compound can change its state when the surrounding temperature or pressure is changed.
At high temperatures (above 100 degrees celsius), it exists in vapour form (the gaseous form of water).
At room temperature, it exists in liquid form. At low temperatures (below 0 degrees celsius), it exists in solid form, which we call ice. Matter can be changed from one state to another by modifying external conditions like pressure and temperature. Crystalline solids can further be classified into four types based on the nature of intermolecular forces. Both have different properties, arising out of differences in structures. Solids can also be of two types – crystalline and amorphous. Matter in a solid state has a higher density compared to that in other states, barring a few exceptions. Matter exists in solid form under high pressure and low temperature conditions. There are general characteristics of the solid state of matter that distinguish it from other states. It exists in three forms around us – solid, liquid, and gas. Matter is defined as anything that occupies space and has mass.
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