Here's why:

* Ionic Compounds: Formed by the electrostatic attraction between positively charged ions (cations) and negatively charged ions (anions).

* Sodium (Na): A metal that readily loses an electron to form a positively charged sodium ion (Na+).

* Chlorine (Cl): A nonmetal that readily gains an electron to form a negatively charged chloride ion (Cl-).

In sodium chloride (NaCl), the sodium ions (Na+) and chloride ions (Cl-) are held together by strong electrostatic forces, forming a crystalline structure.