Wednesday, April 10, 2013

Q 9 Explain (i) The basis of similarities and differences between metallic and ionic crystals. (ii) Ionic solids are hard and brittle.


Q 9 Explain
(i) The basis of similarities and differences between metallic and ionic crystals.
(ii) Ionic solids are hard and brittle.
(i)
The constituent particles of both metallic and ionic crystals are held by strong electrostatic force of attraction. In metals there is strong force of attraction between the mobile electron and positively change ions. In ionic crystals there are strong force of attraction between anion and cation. As both types of crystals have strong force of attraction so there melting and boiling points are high. Metal have free mobile electron so they conduct electricity in all there phase while ionic compound conduct electricity at molten or aqueous state only.  
(ii)
The constituent particles of ionic compound are held by strong electrostatic force of attraction. In ionic crystals there are strong force of attraction between oppositely changed anions and cations. As  the electrostatic force of attraction is very strong so that the charged ions are held in fixed positions and they cannot move easily . This is the reason of ionic crystals to be hard and brittle.

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