Here's why:
* Salt (NaCl) is an ionic compound, meaning it's formed by the electrostatic attraction between positively charged ions (cations) and negatively charged ions (anions).
* In the case of salt, sodium (Na) loses an electron to become a positively charged ion (Na+), and chlorine (Cl) gains an electron to become a negatively charged ion (Cl-).
* These oppositely charged ions then attract each other, forming a strong ionic bond.
* The smallest unit of salt that represents this bond is a molecule consisting of one sodium ion (Na+) and one chloride ion (Cl-) held together by the ionic bond.
Therefore, a single NaCl molecule is the smallest unit of salt that still retains the properties of salt.
