Fluorine (symbol F, atomic number 9) is the most reactive and electronegative of all elements, used in toothpaste and Teflon. It is classified as a halogen and sits in group 17, period 2 of the periodic table.
Overview
Fluorine is the chemical element with atomic number 9 and the symbol F. With a standard atomic weight of 18.998, it is a halogen. In the periodic table it occupies group 17 and period 2, and under standard conditions it is normally a gas. Fluorine is the most reactive and electronegative of all elements, used in toothpaste and Teflon.
Atomic structure
An atom of Fluorine has 9 protons in its nucleus and, when neutral, 9 electrons arranged in the configuration [He] 2s2 2p5. Its standard atomic weight of 18.998 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Fluorine was discovered in 1886 by Henri Moissan. It follows Oxygen (O) and precedes Neon (Ne) in order of atomic number.
| Atomic number | 9 |
|---|---|
| Symbol | F |
| Atomic mass | 18.998 |
| Category | Halogen |
| Group | 17 |
| Period | 2 |
| Electron configuration | [He] 2s2 2p5 |
| Phase at STP | Gas |
| Discovered | 1886 (Henri Moissan) |