Sodium fluoride is a compound formed from sodium and fluorine. The chemical symbol for sodium is Na, and for fluorine is F. When these two elements combine, each sodium atom pairs with one fluoride ion to create sodium fluoride, resulting in the simple and straightforward chemical formula NaF. This reflects the 1:1 ratio of sodium ions to fluoride ions in the compound, making it the correct representation.
In contrast, the other options feature different compounds and combinations of elements. NaCl is the formula for sodium chloride, commonly known as table salt, which is made from sodium and chlorine. KF represents potassium fluoride, a different compound involving potassium and fluorine. Lastly, CaF2 denotes calcium fluoride, which consists of calcium and fluorine in a 1:2 ratio. Each of these alternate formulas corresponds to distinct substances with different chemical compositions, which is why they do not represent sodium fluoride.