Behaviour Of Solids:-
OR
Properties Of Solid:-
1) Definite Shape:-
In solids particles are more closed to each other and have no translational motion due to which each particle keep its definite position so the solid have definite shape.
2) Diffusion:-
Generally in solids there is no diffusion, so the solid particle have no translational motion so they can not diffuse in each other. Some solids have negligible diffusion due to vibration of particles.
3) Compression Or Compressibility:-
Solid are incompressible by pressure because there is no free space between the particles of solids.
4) Deformation:-
Change in shape of solid by pressure is called deformation. Solids which are elastic their shape is deformed by giving high pressure on them.
5) Metling:
Change of solid in to liquid by heating is called melting. When a solid is heated kinetic energy of its particles increases due to which vibration of the particles increases and the force of attraction between the particles decreases so the particles start moving thus a solid changes to a liquid.
6) Sublimation:
Change of a solid direct in to vapours by heating and change of vapours direct in to solid by cooling without being liquid is called sublimation.
Some solid have low force of attraction between their particles which dissociate by heating and the particles become free and change in to vapours.
Example
Naphthalene, camphor, Iodine, and dry Ice are some solid which sublime.
Classifiction of Solids:-
There are two main types of solids
Crystalline solids.
Amorphous solids.
1) Crystalline Solids:-
Solid which have definite geometrical arrangement of particles are called crystalline solids.
Example
Sodium chloride, Copper sulphate, Silver nitrate, Ice, Gold And zinc etc.
Properties of Crystalline Solid:
Crystalline solids have following properties.
1) Crystalline solid have definite arrangement of particles so they have a definite shape.
2) Crystalline solid have sharp melting point due to uniform force of attraction at every where.
3) Crystalline solids have definite plane of cleavage, thus when a big crystal is decomposed in to smaller cystal, then all the smaller crystals have same shape.
4) crystalline solids are ans isotropic. An isotropy is the change in intensity of physical property in the different direction.
5) crystalline solids are symmetrical.
2) Amorphous Solid:-
Solids which have no definite geometrical arrangement of particles Or Solids which have random arrangement of particles are called amorphous solids.
Example
Solids in powder form, plastics, glass and rubber.
Properties of Amorphous Solids:
Amorphous solid have following properties.
1) Amorphous solids have random arrangement of particles so they have no definite shape.
2) Amorphous solid have wide melting point and become soft on heating and melt slowly.
3) Amorphous solid have no definite plane of cleavage.
4) Amorphous solids are isotropics. Isotropy is the same intensity of physical property in every direction.
5) Amorphous solids are unsymmetrical.
Types Of Crystals (Crystalline solids):-
There are three types of crystals.
1) Atomic Crystals:-
Crystals which are made of atoms of same type are called atomic crystals. Atomic crystals are element and are represented by symbols. There are two types of atomic crystals, metallic crystals and covalent crystals.
i) Metallic Crystals:-
Crystal which are made of metal atoms bounded by metallic bond are called metallic crystal.
Example
Sodium Na
Calcium Ca
Zinc Zn
Silver Ag
Gold Au
Copper Cu etc
Properties of Metallic Crystals:-
• Metallic crystals are hard and have high melting point.
• They are elastic.
• They are good conductors of heat and electricity.
• They are lustrous.
• They are ductile and malleable. Ductility is the property of a metal to be changed oj to wire and malleability is the property of a metal to be changed on to sheet or foil.
ii) Covalent Crystals:-
Crystals which are made of nonmetal atoms bounded by covalent bond are called covalent crystals.
Example
Diamond, Graphite made of carbon, Sulphur and Phosphorous.
Properties of Covalent Crystals:-
• Covalent crystals are hard and have high melting point.
• They are inelastic.
• They are bad conductors of electricity and heat.
• They have low density
• They have high refractive index.
2) Ionic Crystals:-
Crystals which are made of ions ( cation and anion) bounded by ionic bond are called ionic crystals.
Example
NaCl
MgO
CaCO3
CaCl2 etc.
Properties of Ionic Crystals:-
• Ionic crystals are hard and have high melting point.
• They are inelastic.
• They are non conductor of electricity in solid state but good conductors in solution form or molten state (liquid state) and are called electrolytic conductors.
• They are soluble in water.
3) Molecular Crystal:-
Crystals which are made of molecules bounded by vander wall's force of attraction or Hydrogen bond are called molecular crystals.
Example
Iodine, Camphir, Naphthalene and Ice etc.
Properties of Molecular Crystals:
• Molecular crystals are soft and have low melting point.
• They have low boilling point.
• They are bad conductors of electricity and heat .
• They are inelastic.
• Generally they are volatile and change in to vapours on heating.
• Their dipole force are weaker than ionic bond
• Their dipole force are also weak then covalenr bond.
• The relatively intermolecular forces which are weak just because of molecular solids to have relatively low melting points.
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