The melting points and boiling points of some ionic compounds

The melting points and boiling points of some ionic compounds are given below:

These compounds are termed ionic because they are formed by the transfer of electrons from a metal to a non-metal. The electron transfer in such compounds is controlled by the electronic configuration of the elements involved. Every element tends to attain a completely filled valence shell of its nearest noble gas or a stable octet.

1. Show the electron transfer in the formation of magnesium chloride. 
2. List two properties of ionic compounds other than their high melting and boiling points. 
3. (A) While forming an ionic compound say sodium chloride how does sodium atom attain its stable configuration ?

 (B) Give reasons :

i. Why do ionic compounds in the solid state not conduct electricity ?
ii. What happens at the cathode when electricity is passed through an aqueous solution of sodium chloride ? 

Answer

i.

ii. 

• They are hard solids
• They are soluble in water
• They conduct electricity in aqueous solution or molten state

iii. 

(A) • Sodium atom has one electron in its outermost shell
• It attains its nearest noble gas configuration by losing this electron

(B). 

1. Because movement of ions in the solid is not possible due to their rigid structure.
2. H₂ gas is liberated at cathode