Fluorine (F) - Element 9 | Properties & Electron Configuration
What is Fluorine?
Fluorine (F) is element 9, a halogen in period 2, group 17. Its electron configuration is 1s² 2s² 2p⁵.
| Atomic Number | 9 |
| Symbol | F |
| Atomic Mass | 18.998 u |
| Category | Halogen |
| Period | 2 |
| Group | 17 |
| Block | p |
| Electron Configuration | 1s² 2s² 2p⁵ |
| Short Config | [He] 2s² 2p⁵ |
| Electronegativity | 3.98 |
| Atomic Radius | 71 pm |
| Ionization Energy | 1681 kJ/mol |
| Electron Affinity | 328 kJ/mol |
| Phase (STP) | Gas |
Electron Configuration
The full electron configuration of Fluorine is 1s² 2s² 2p⁵. In noble gas shorthand, this is written as [He] 2s² 2p⁵.
Fluorine is a p-block element in group 17, period 2.
Periodic Trends
Electronegativity: Fluorine has a Pauling electronegativity of 3.98. Within group 17, electronegativity generally decreases down the group.
Atomic Radius: 71 pm. Across period 2, atomic radius generally decreases left to right as nuclear charge increases.
Ionization Energy: 1681 kJ/mol. Ionization energy generally increases across a period and decreases down a group.
View all 118 elements with trend overlays for electronegativity, atomic radius, ionization energy, and electron affinity.
Explore Fluorine on the Interactive Periodic TableRelated Topics
Chlorine (Cl)
Properties of Chlorine - same group as Fluorine
Bromine (Br)
Properties of Bromine - same group as Fluorine
Iodine (I)
Properties of Iodine - same group as Fluorine
Lithium (Li)
Properties of Lithium - same period as Fluorine
Beryllium (Be)
Properties of Beryllium - same period as Fluorine
Boron (B)
Properties of Boron - same period as Fluorine