An ionic bond is formed by the electrostatic attraction between oppositely charged ions.

Here's a breakdown:

* Ions: Atoms that have gained or lost electrons, resulting in a net positive or negative charge.

* Electrostatic Attraction: The force of attraction between opposite charges.

For example, in table salt (NaCl), sodium (Na) loses an electron to become a positively charged ion (Na+), while chlorine (Cl) gains an electron to become a negatively charged ion (Cl-). The strong attraction between these oppositely charged ions forms the ionic bond.