Fluorine has 10 neutrons in its nucleus. This element has nine protons, as well as nine electrons in two energy levels. Fluorine is a green element that is classified in the halogen family, or Group 17, on the periodic table.
Fluorine's name is derived from the Latin word "fluere," which means "flow." Fluorine does not exist freely in nature, and it is considered the most reactive of all elements. Due to this, scientists were unable to isolate fluorine until 1886 when Henri Moissan was successful in isolating the element by the electrolysis of hydrofluoric acid and potassium fluoride. He was awarded the Nobel Prize in Chemistry in 1906 for his work.