Answer the following question:
 
Explain formation of ionic compounds.
 
i. Electronic configuration:
 
Calcium - (\(2, 8, 8, 2\)).
 
Oxygen- (\(2, 6\)).
   
ii. Ion formation:
Calcium atom electron and becomes  
   
Oxygen atom that electron and becomes
   
The anion and cation are held together by electrostatic force forming an ionic compound called .