Question

Explain the formation of onions and vations in ionic compound through examples symbols formulae

Answer 1

Ionic compounds on the other had have atoms or molecules that bond to one another through their mutual attraction between positive and negative charges: Positively charged atoms or molecules are called "cations" and negatively charged atoms or molecules are called "anions". Thus cations and anions attract one another.

Na+ has its outer most shell i.e valency 1 
and Cl- has its valency 7 

So, Na+ give its ion to Cl- to complete its octave and form NaCl ....

Na -1e=Na1+
Cl+1e=Cl1-