What is ionic bonding?

Ionic bonding by definition is the electrostatic forces of attraction between oppositely charged ions. What this means is, when metal atoms lose an electron to become a positively charged ion (Na+) and non-metal atoms gain an electron to become a negatively charged ion (e.g Cl-), the positive ion and negative ion will be attracted towards eachother (opposites attract) and a strong bond will form; an ionic bond.