Chapter – 1 Solid state
Types of solids:Based on the on the arrangement of particle,s solids are broadly classified into two
types.
a)Crystalline solids.
b)Amorphous solids.
Differences between crystalline and amorphous Solids:
Crystalline solids Amorphous solids
(i) They have definite geometric shape. No definite geometric shape.
(ii) Arrangement of constituent particles Arrangement of constituents particles are random.
(atoms, ions or molecules) is ordered, They show only short range
order is long range order. order.
(iii) They have sharp melting point because of long They melt over a range of temperature and
range order all interactions between particles can be moulded and blown in various shapes
are broken at one temperature uniform melting because of short range order.
(iv) Cleavage property of solids: when crystalline A amorphous solids break unevenly. They breaks
solid is broken it gives up in to uneven powder particles
crystals with proper edges, – formless, shapeless.
faces and corner
v Crystalline solids are anisotropic in nature Amorphous solids on the other hand are
i.e., some of their physical properties like isotropic in nature.
electrical resistance or refractive index show Reason: No long range order in them and
different values when measured along arrangement is irregular along all directions.
different direction.
By nature, they are true solids.
B D
C
A
Reason: Due to different arrangement of particles
in different directions as a result of long range order.
Crystalline solids are true solids as they show Amorphous solids are false solids as they
only the properties of solids. show properties not of solids but are liquid
Example- quartz SiO2, diamond, SiC. specially fluidity. Glass is super cooled liquid.
silicon carbide ,metals.
Ex: Diamond, quartz, NaCl, etc. Ex: glass, rubber, plastics, amorphous,silicon etc.
1
, Classification of crystalline solids based on nature of intermolecular forces
(i) Molecular solids
(ii) Ionic solids
(iii) Metallic solids
(iv) Covalent solids
(i) Molecular solids
Constituent particles: molecules
These are futher classified into further classified into,
(a) Non-polar molecular solids:
Constituent particles: either atoms (Ex: Argon, He etc) or molecules formed by non-polar covalent bonds
(Eq : H2, Cl2, and l2) (electro negativity difference between atoms = 0)
Bonding or attractive forces: Weak dispersion forces or London forces
Properties of solids: Soft, non-conductors of electivity low melting point, usually liquids or gas at room
temperature and pressure.
Polar molecular solids:
Constituent particles: molecules formed by polar covalent bonds Eq: HCl, SO2
Bonding or attractive forces: relatively strong dipole-dipole interaction bad conductor of electricity as there are no
electron or free ions non-polar solids. Liquids or gases at room temperature and pressure. Eq: SO2, HCl, NH3
Hydrogen bonded molecular solids:
Constituent particles: The molecules of solids containing polar covalent bonds between H and F, O or N atoms.
Bonding / attractive forces: hydrogen bonding
Properties: They are harder than polar or non – polar molecular solids.
Higher melting point compared to polar and non – polar solids.
(Interaction – hydrogen bonding)
They do not conduct electricity as there are no free ions.
Under normal conditions of temp and pressure, these exist as volatile liquids or soft solids.
Eq: H2O, HF, NH3 etc
(ii) Ionic solids
Constituent particles: Ions, both cations (+ve) and anions (–ve)
Bonding /attractive forces: Strong coulombic (electrostatic) forces
Properties: Hard and brittle solids, high melting points, since no mobile ions in solid state, they are
electrical insulators but electrical conductors in molten or aqueous state Eq: NaCl, ZnS, CaCl2
etc
(iii) Metallic solids
Constituent particles: Orderly collection of positive metal ions (Kernels) held together by sea of mobile electrons
contributed by metal atoms which may range from one or more.
Bonding / attractive forces: Metallic bond
Metallic bonding is the interaction between positively chemical ion kernels and e− gas/cloud –
interactive force.
Properties: Mobile electrons carry current and heat. Metallic solids have high electrical and
thermal conductivity. Excitation of mobile electrons results in lustre and colour in certain cases.
Metals are highly malleable and ductile with high melting point. Eq: Fe, Cu, etc
2
, (iv) Covalent / network solids
Constituent particles: Atoms which are bonded covalently throughout the crystal also called gaint molecules.
Bonding / attractive forces: strong and direction covalent bonding.
Properties: Hard and brittle with extremely high melting point and even decompose before melting insulators and do not
conduct electricity.
Eq : Diamond and silicon carbide, graphite etc.
Type of Constituent Bonding Physical Electrical conductivity Melting Examples
solids particles /attractive nature point
force
molecular Non – Dispersion soft insulator very low Ar, CCl4 H2, I2, CO2
solid
polar or
Non- polar Molecules
London
forces
Polar polar– Dipole - soft Insulator Very HCl, SO2
molecules dipole low
Hydrogen Hydrogen Hydrogen Hard Insulator low H2O (ice)
bonded bonded
molecules bonding
Ionic solids ions Coulombic Hard,but Insulators in solid High NaCl, MgO, ZnS, CaF2
brittle
or state but conductors
electrostatic
in molten state and
ionic
bonds in aqueous solutions.
Metallic Positive Metallic Hard but Conductors in solid Fairly Fe, Cu, Ag, Mg
solids bonding malleable and high
ions in a sea ductile state as well as in
ofdelocalised molten state
electrons
Covalent Atoms Covalent Hard Insulators high SiO2,(quartz)
solids bonding
SiC,C(diamond) AlN,
C(graphite)
Graphite (c) – Conductor, soft
3
Types of solids:Based on the on the arrangement of particle,s solids are broadly classified into two
types.
a)Crystalline solids.
b)Amorphous solids.
Differences between crystalline and amorphous Solids:
Crystalline solids Amorphous solids
(i) They have definite geometric shape. No definite geometric shape.
(ii) Arrangement of constituent particles Arrangement of constituents particles are random.
(atoms, ions or molecules) is ordered, They show only short range
order is long range order. order.
(iii) They have sharp melting point because of long They melt over a range of temperature and
range order all interactions between particles can be moulded and blown in various shapes
are broken at one temperature uniform melting because of short range order.
(iv) Cleavage property of solids: when crystalline A amorphous solids break unevenly. They breaks
solid is broken it gives up in to uneven powder particles
crystals with proper edges, – formless, shapeless.
faces and corner
v Crystalline solids are anisotropic in nature Amorphous solids on the other hand are
i.e., some of their physical properties like isotropic in nature.
electrical resistance or refractive index show Reason: No long range order in them and
different values when measured along arrangement is irregular along all directions.
different direction.
By nature, they are true solids.
B D
C
A
Reason: Due to different arrangement of particles
in different directions as a result of long range order.
Crystalline solids are true solids as they show Amorphous solids are false solids as they
only the properties of solids. show properties not of solids but are liquid
Example- quartz SiO2, diamond, SiC. specially fluidity. Glass is super cooled liquid.
silicon carbide ,metals.
Ex: Diamond, quartz, NaCl, etc. Ex: glass, rubber, plastics, amorphous,silicon etc.
1
, Classification of crystalline solids based on nature of intermolecular forces
(i) Molecular solids
(ii) Ionic solids
(iii) Metallic solids
(iv) Covalent solids
(i) Molecular solids
Constituent particles: molecules
These are futher classified into further classified into,
(a) Non-polar molecular solids:
Constituent particles: either atoms (Ex: Argon, He etc) or molecules formed by non-polar covalent bonds
(Eq : H2, Cl2, and l2) (electro negativity difference between atoms = 0)
Bonding or attractive forces: Weak dispersion forces or London forces
Properties of solids: Soft, non-conductors of electivity low melting point, usually liquids or gas at room
temperature and pressure.
Polar molecular solids:
Constituent particles: molecules formed by polar covalent bonds Eq: HCl, SO2
Bonding or attractive forces: relatively strong dipole-dipole interaction bad conductor of electricity as there are no
electron or free ions non-polar solids. Liquids or gases at room temperature and pressure. Eq: SO2, HCl, NH3
Hydrogen bonded molecular solids:
Constituent particles: The molecules of solids containing polar covalent bonds between H and F, O or N atoms.
Bonding / attractive forces: hydrogen bonding
Properties: They are harder than polar or non – polar molecular solids.
Higher melting point compared to polar and non – polar solids.
(Interaction – hydrogen bonding)
They do not conduct electricity as there are no free ions.
Under normal conditions of temp and pressure, these exist as volatile liquids or soft solids.
Eq: H2O, HF, NH3 etc
(ii) Ionic solids
Constituent particles: Ions, both cations (+ve) and anions (–ve)
Bonding /attractive forces: Strong coulombic (electrostatic) forces
Properties: Hard and brittle solids, high melting points, since no mobile ions in solid state, they are
electrical insulators but electrical conductors in molten or aqueous state Eq: NaCl, ZnS, CaCl2
etc
(iii) Metallic solids
Constituent particles: Orderly collection of positive metal ions (Kernels) held together by sea of mobile electrons
contributed by metal atoms which may range from one or more.
Bonding / attractive forces: Metallic bond
Metallic bonding is the interaction between positively chemical ion kernels and e− gas/cloud –
interactive force.
Properties: Mobile electrons carry current and heat. Metallic solids have high electrical and
thermal conductivity. Excitation of mobile electrons results in lustre and colour in certain cases.
Metals are highly malleable and ductile with high melting point. Eq: Fe, Cu, etc
2
, (iv) Covalent / network solids
Constituent particles: Atoms which are bonded covalently throughout the crystal also called gaint molecules.
Bonding / attractive forces: strong and direction covalent bonding.
Properties: Hard and brittle with extremely high melting point and even decompose before melting insulators and do not
conduct electricity.
Eq : Diamond and silicon carbide, graphite etc.
Type of Constituent Bonding Physical Electrical conductivity Melting Examples
solids particles /attractive nature point
force
molecular Non – Dispersion soft insulator very low Ar, CCl4 H2, I2, CO2
solid
polar or
Non- polar Molecules
London
forces
Polar polar– Dipole - soft Insulator Very HCl, SO2
molecules dipole low
Hydrogen Hydrogen Hydrogen Hard Insulator low H2O (ice)
bonded bonded
molecules bonding
Ionic solids ions Coulombic Hard,but Insulators in solid High NaCl, MgO, ZnS, CaF2
brittle
or state but conductors
electrostatic
in molten state and
ionic
bonds in aqueous solutions.
Metallic Positive Metallic Hard but Conductors in solid Fairly Fe, Cu, Ag, Mg
solids bonding malleable and high
ions in a sea ductile state as well as in
ofdelocalised molten state
electrons
Covalent Atoms Covalent Hard Insulators high SiO2,(quartz)
solids bonding
SiC,C(diamond) AlN,
C(graphite)
Graphite (c) – Conductor, soft
3
