When is a ionic bond is formed?

Answer 1

for an ionic bond to form one atom should lose electron to form cation whereas the other atom should gain electron to form anion

ionic bond is the interaction between the cations and the anions

Answer 2

When a positively charged, metal ion (for example sodium [Na]+) joins with a negatively charged, non-metal ion (eg. [Cl]-) to form a compound whose overall charges cancel out, make it electrically neutral and thus the elements that make up the compound are stable and unreactive.