Look up Flour - ground wheat, or similar cereal, etc. Using in cooking. Fluorine - an element of the periodic table. A halogen from memory. A pale yellow gas at room temperature, highly reactive, poisonous, not likely sold at a supermarket, in elemental form. https://en.wikipedia.org/wiki/Fluorine In toothpaste, probably fluoride a combination of Fluorine and something else. eg Sodium monofluorophosphate

You are confusing to two similar-looking words: "flour" and "fluorine." They are completely different. "Flour" means "harina," usually "harina de trigo." It is a food. It is a white powder made from wheat. It is used in baking. It is used to make bread and cake. You buy it in the supermarket. Notice that the order of the letters is O-U. It is spelled almost phonetically. It is pronounced exactly the same way as the word "flower" (flor!) The chemical element is "fluorine." There is no word "fluor." Notice that the order of the letters is U-O. Notice that it ends in -ine. It is pronounced "floor-een." Fluorine has the chemical symbol F, and atomic number 9. It is a halogen like chlorine. It is very reactive, very toxic, and very dangerous. You cannot buy fluorine in a supermarket! When fluorine combines with other elements, it forms salts which are named fluoride. Examples are stannous fluoride and sodium fluoride. Fluorides are included in toothpaste to prevent tooth decay. So, you cannot buy fluorine in a supermarket, but you might buy toothpaste that contains fluoride as an ingredient.

Hello Martin, I am guessing the "flour" your app was referring to is flour used for baking. Flour is used to bake almost all bread type products, including cakes and pastries. That would be the most common use of "flour" in regards to grocery shopping.