Fluorine is a highly reactive, pale yellow gas at room temperature. It is commonly found in the crust of the Earth (it is the 13th most common element) as a part of certain minerals, such as fluorite. It is a chemical element with the atomic number 9 and represented by the chemical symbol F. Fluorine is one of only 26 chemical elements that only have one stable isotope (these are known as monoisotopic elements). However, many other isotopes of fluorine have been identified.
How many isotopes does fluorine have?
The stable isotope of fluorine is known as fluorine-19 (19F). It makes up 100% of all of the naturally occurring fluorine on Earth.
There are 17 other unstable (radioactive) isotopes of fluorine from 14F to 31F. Of these unstable isotopes, 18F has the longest half life at just 109.771 minutes. The remaining radioactive isotopes all have half lives of less than a minute and most are less than a second. Both 28F and 30F have half lives of less than a millisecond!
One isomer (the same compound, but a different energy state), 18mF, of fluorine has been identified. It has a half life of 162 nanoseconds.
Due to the short half lives of these isotopes they have few uses. However, 18F has important uses in the medical industry. It can be used as a tracer in PET scans, which are used for diagnosing many conditions including cancer. The stable isotope (19F) is also used in medical imaging. It is used in nuclear magnetic resonance scanning to study the metabolism, lung ventilation and protein structures.