Why aren't the properties of sodium chloride the same as the elements that compose it?

Answer 1

The easiest answer is that there has been a chemical change and the properties of the products are not the same as the reactants.
One atom of the element Na has lost an electron to become a sodium ion (a cation) and one atom of the element Cl has gained an electron to become a chloride ion (an anion). The properties are not the same because a chemical reaction has taken place.

Answer 2

Oh I see, thank you!