Final answer:
Fluorine is a highly reactive nonmetal with seven valence electrons. It often gains one electron to form fluoride (F⁻), an anion necessary for bone and tooth health.
Step-by-step explanation:
Fluorine is a nonmetal that belongs to Group 7A of the periodic table. This element, which is essential for the health of bones and teeth, has an atomic number of 9, which means a fluorine atom also has 9 electrons. To answer your question, Fluorine has seven valence electrons, which are the electrons in the outermost shell used for bonding with other atoms. It often forms an anion by gaining one electron to achieve a full valence shell of eight electrons, becoming fluoride (F⁻).
The concept of valence electrons is important as it governs how atoms interact and bond with each other. Fluorine's tendency to gain an electron to fill its valence shell makes it highly reactive and a strong oxidizing agent. Considering its position on the periodic table, traditionally, any element found on the right side is classified as a nonmetal.