* One atom (the metal) loses one or more electrons to become a positively charged ion (cation).

* The other atom (the nonmetal) gains these electrons to become a negatively charged ion (anion).

* The electrostatic attraction between the oppositely charged ions holds them together in a strong bond.

Here's a breakdown:

1. Electronegativity: Ionic bonds typically form between elements with significantly different electronegativities. Electronegativity is the ability of an atom to attract electrons. Metals have low electronegativity, while nonmetals have high electronegativity.

2. Electron Transfer: The atom with lower electronegativity (the metal) loses electrons to the atom with higher electronegativity (the nonmetal). This electron transfer creates ions with opposite charges.

3. Electrostatic Attraction: The opposite charges of the ions attract each other, forming a strong electrostatic force that holds them together in a crystal lattice structure.

Example:

Sodium (Na) has one valence electron and a low electronegativity. Chlorine (Cl) has seven valence electrons and a high electronegativity.

* Sodium loses its valence electron to become a positively charged sodium ion (Na+).

* Chlorine gains the electron to become a negatively charged chloride ion (Cl-).

* The oppositely charged ions attract each other, forming an ionic bond and creating sodium chloride (NaCl), also known as table salt.

Key Points:

* Ionic bonds usually form between metals and nonmetals.

* They result from the transfer of electrons, not sharing.

* The resulting ions have opposite charges and are strongly attracted to each other.

* Ionic compounds have high melting and boiling points due to the strong electrostatic forces.

* They are usually hard and brittle.