On the basis of magnetic behavior solids are divided into five types
(1)PARAMAGNETIC SUBSTANCES:-The substances which are weakly attracted by the magnetic field are called paramagnetic substances and the phenomenon is known as paramagnetism.E.g. Cu2+,Fe3+,Cr3+ etc.Paramagnetism occurs due to the presence of paired electrons.
(2)DIAMAGNETIC SUBSTANCES: - The substances which are weakly repelled by the magnetic field are called diamagnetic substances and the phenomenon is known as diamagnetism.E.g. NaCl,H2O, Benzene etc.Diamagnetism occurs due to the presence of unpaired electrons.
(3)FERROMAGNETIC SUBSTANCES:-The substances which are strongly attracted by the magnetic field are called ferromagnetic substances and the phenomenon is known as ferromagnetism.E.g. Fe, Ni, Co etc.Ferromagnetism arises due to the alignment of magnetic moments in parallel direction.
Alignment of magnetic moments
(4)ANTI-FERROMAGNETIC SUBSTANCES:-The substances which have zero net magnetic moment are called anti-ferromagnetic substances.E.g. MnO,V2O3 etc.Anti -ferromagnetism arises due to the alignment of magnetic moments in parallel and antiprallel directions in such a way that they cancel each other and hence the net magnetic moment comes out to be zero.
Alignment of magnetic moments
(5)FERRIMAGNETIC SUBSTANCES: - The substances which have small net magnetic moment are called ferrimagnetic substances and the phenomenon is known as ferrimagnetism.E.g.Fe3O4 (magnetite) etc.Ferrimagnetism arises due to the alignment of magnetic moments in parallel and anti-parallel directions in unequal number. Hence they possess small net magnetic moment.
Alignment of magnetic moments
DIELECTRIC PROPERTIES OF SOLIDS
Dielectric substances are insulators which are polar in nature and have permanent electric dipoles.
These polar crystals show following properties.
PIEZOELECTRICITY: - In some polar crystals electricity is produced when pressure is applied this is called piezoelectricity.E.g. Lead zirconate, Barium titanate, Quartz etc.
PYROELECTRICITY:-When some polar crystals are heated electricity is produced this is known as pyroelectricity. E.g. Lead zirconate, Quartz etc
FERROELECTRICITY: - In some polar crystals the electric dipoles are permanently aligned in a particular direction even in the absence of electric field. This is known as ferroelectricity .E.g. Rochelle salt, Barium titanate etc.
ANTI-FERROELECTRICITY:- In some polar crystals the electric dipoles are aligned in such a way that their dipole moments cancel each other and hence they possess zero net dipole moment. This is known as antiferroelectricity.E.g. Lead zirconate etc.
SOLID STATE TEST
Q:-Define doping and p-type semi conductors.
Q: - Quartz is a crystalline form of silica whereas glass is an amorphous form of silica .why?
Q: - Glass is called pseudo solid or super cooled liquid .Why?
Q:-The edge length of NaCl is 564 pm .calculate density. Atomic mass of sodium is 23 g/mol and that of chlorine is 35.5 g/mol.
Q:-Calculate the number of atoms in all the three cubic unit cells.
Q: - What is the effect of temperature and pressure on the coordination number of solids
Q:-Differentiate between Schottky and Frenkel defects.
Q: - Why does ZnO appear yellow on heating.
Q: - What are F-centers?
Q: - What is the effect of temperature on the conductivity of metallic conductors and electrolytic conductors?
Q:- What are primitive and non-primitive unit cells ?
Q:- Give an example of metals showing ccp and hcp close packing?
Q:- Explain fcc close packing with diagrams.
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