(a)What is the electronic configuration of (i) a sodium atom, and (ii) an oxygen atom?(b) What is the number of outermost electrons in (i) a sodium atom, and (ii) an oxygen atom?
(c) Show the formation of Na₂O by the transfer of electrons between the combining atoms.
(d) Why are ionic compounds usually hard?
(e) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state?

 

(c) The formation of Na₂O by the transfer of electrons between the combining atoms is given below:

(d) Ionic compounds are usually hard because they have oppositely charged ions that attract each other strongly and forms a crystal structure.

(e) Solid ionic compounds are made up of ions but do not conduct electricity because they are held together by a strong electrostatic force of attraction that restricts the movement. On dissolving in water, the crystal structure is broken and ions move freely. Therefore, it conducts electricity.