* Electron Transfer: Ionic compounds form when a metal atom loses electrons (becoming a positively charged ion - a cation) and a nonmetal atom gains those electrons (becoming a negatively charged ion - an anion). This transfer of electrons creates an electrostatic attraction between the oppositely charged ions.

* Metal and Nonmetal: Metals tend to lose electrons easily due to their low electronegativity, while nonmetals have a high electronegativity and readily gain electrons.

Examples of Ionic Compounds:

* Sodium chloride (NaCl): Sodium (Na, a metal) loses an electron to become Na+, and chlorine (Cl, a nonmetal) gains an electron to become Cl-. The resulting ions attract each other to form the compound.

* Magnesium oxide (MgO): Magnesium (Mg, a metal) loses two electrons to become Mg2+, and oxygen (O, a nonmetal) gains two electrons to become O2-.

Key Characteristics of Ionic Compounds:

* High melting and boiling points: The strong electrostatic forces between ions require a lot of energy to break.

* Solid at room temperature: The strong forces hold the ions rigidly in a crystal lattice.

* Conduct electricity when molten or dissolved: The free movement of ions allows for the conduction of electricity.

* Often soluble in water: The polar water molecules can interact with the charged ions, breaking apart the ionic lattice.

Let me know if you have any other questions!