Here's why:
* Sodium (Na) is a metal, and Fluorine (F) is a non-metal. They are distinct elements with different chemical properties.
* They bond together chemically: Sodium loses one electron to become a positively charged sodium ion (Na+), while fluorine gains one electron to become a negatively charged fluoride ion (F-). The electrostatic attraction between these oppositely charged ions forms the ionic bond that holds the compound together.
* Fixed ratio: The compound always has one sodium ion for every fluoride ion, resulting in a fixed ratio of 1:1.
Therefore, sodium fluoride meets all the criteria to be classified as a chemical compound.
