Here's why:

* Ionic compounds are formed by the electrostatic attraction between positively charged ions (cations) and negatively charged ions (anions).

* Table salt (NaCl) is formed when a sodium atom (Na) loses an electron to become a positively charged sodium ion (Na+) and a chlorine atom (Cl) gains an electron to become a negatively charged chloride ion (Cl-).

* These oppositely charged ions then attract each other strongly, forming a crystalline structure.

Therefore, salt is a crystalline ionic compound made of sodium and chloride ions.