Video Transcript
Lithium and fluorine react to form a salt with the formula LiF. What is the name of this salt?
The question tells us that the compound we are naming is a salt. A salt is defined as a chemical consisting of both cations, which are positively charged ions, and anions, which are negatively charged ions. This means that a salt with the chemical formula LiF is an ionic compound between lithium and fluorine. The chemical formula we are given contains the symbol Li, which represents lithium, and the symbol F, which represents fluorine.
We can find these elements using the periodic table, where we will find lithium in group one. The dotted zigzag line on the periodic table indicates the position of the metalloids, and elements that lie to the left of this are metals. And therefore, lithium is a metal and will form a cation. Fluorine is found in group 17 to the right of the dotted zigzag line. It is a nonmetal and therefore forms an anion. This is significant because when naming a salt, we first write the name of the cation followed by the name of the anion.
The name for a metal cation with only one possible charge is the same as the metal’s name on the periodic table. Lithium forms only one plus ions. So, for its cation name, we would use its element name exactly as it is shown on the periodic table. Therefore, for the first part of this salt’s name, we write lithium.
The name for an anion composed of only one element consists of the root of the element’s name with the ending -ide. Therefore, we would take the root of fluorine, which is “fluor,” and add -ide to the ending. This gives us the anion name of fluoride. Therefore, the complete name of this salt is lithium fluoride.
