Explain the following with suitable examples
(i) Ferromagnetism
(ii) Paramagnetism
(iii) Ferrimagnetism
(iv) Antiferromagnetism
(v) 12-16 and 13-15 group compounds
(vi) Pyroelectricity
Answers
Answer:
Ferromagnetism: few substances like iron, cobalt, nickel, gadolinium and CrO2 are strongly attracted by a magnetic field. Such substances are known as ferromagnetic substances. These substances can be permanently magnetised with the help of strong electrostatic field. The metal ions of ferromagnetic substances are grouped together into small regions called domains in solid state. So that each domain acts as a tiny magnet. The domains of un magnetized piece of a ferromagnetic are randomly oriented so that their magnetic moments get cancelled out. When such substance is placed in a magnetic field, all the domains get oriented in the direction of the magnetic field and a strong magnetic effect is produced. This ordering of domains remains same even when the magnetic field is removed and the ferromagnetic substance becomes a permanent magnet.(ii) Paramagnetism :–
few substances like O2, Cu2+, Fe3+, Cr3+ are weekly attracted by a magnetic field.
These substabces are magnetised in a magnetic field in the same direction. When we remove magnetic field ,they lose their magnetism. paramagnetism is takes place due to presence of one or more unpaired electrons. These unpaired electron are attracted by the magnetic field.
(IV)Antiferromagnetism:
Antiferromagnetic substances have domain structure similar to ferromagnetic substance. The domains of antiferromagnetic substance are oppositely oriented and cancel out each other's magnetic moment . Example MnO is a Antiferromagnetic substance.
(V)12–16 and 13–15 group compounds.
The compounds of 12–16 group are prepared by combining elements of group 12 and group 16. While the compound of 13–15 group compounds are prepared by combining elements of group 13 and group15. These compounds are covalent and there ionicity depends up the difference in electro negativities of elements which involve in forming of these compounds. These compounds have special electrical and optical properties so that these compounds are used in industries for a variety of applications
Examples
ZnS, CdS ,CdSe and HgTe are example of 12–16 group compounds
InSb, AIP and GaAs are the example of 13–15 group compounds
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