Fluorine-18 is created from bombardment of O-18 with a hydrogen ion in an accelerator or in a reactor with neutron bombardment of Lithium-6 followed by the resultant tritium combining with O-16 to form F-18. There may be places in the universe where a little of this may be going on but for all purposes it is not naturally occurring on Earth.
As for "abundance"... it depends on how many cyclotrons and target O-18 are used each day to create F-18 for FDG scanning and F-18 bone scanning.
With a 110 minute half-life, any given day's dose is gone by the next...
Not very abundant. See link for some examples. Note that it never occurs in nature as the free Fluorine gas, because it reacts with pretty much everything, so it will be found in nature as the fluoride ion in a compound.
100%
Fluorine or Fluorite is natural to the earth's crust and is found in rocks, coal and other natural formations. It is the Earth's thirteenth most abundant element and around four million tons of it are extracted yearly from mines in Western Europe, China and Mexico.
Fluorine seems a likely answer
Fluorine.
fluorine stable fluorine diatomic is unstable
Fluorine is an element. It occurs naturally.
The most abundant halogen on Earth is chlorine. It is commonly found in seawater, salt deposits, and as part of various minerals.
There is only one abundant isotope of fluorine and that is 19FFluorine-19 is the most common isotope, its abundance is classed as 100% because no other Fluorine isotopes exist in significant quantities. It is also the only stable Fluorine isotope.
Iodine is very less abundant compared to fluorine and chlorine and it is found in seawater also with chlorides,bromides etc and certain forms of marine life also contain Iodine in their systems.Eg Seaweeds
Fluorine or Fluorite is natural to the earth's crust and is found in rocks, coal and other natural formations. It is the Earth's thirteenth most abundant element and around four million tons of it are extracted yearly from mines in Western Europe, China and Mexico.
Fluorine was discovered by Karl Scheele in 1771, recognized as a halogen in 1825, and included in Mendeleev's periodic table of 1869. Fluorine is so active that it existed only in compounds and all efforts to isolate the element failed. Because of its high corrosiveness/toxticity, early fluorine chemists died from fluorine poisoning and the element was dubbed "Tiger of Chemistry." Fluorine, from Latin "fleure" meaning to flow, is the 13th most abundant element in the earth's crust and the most reactive of all elements--it even forms compounds with noble gases.
Astatine, with a molecular weight of 210 amu.
Fluorine
Fluorine is an element and barium is also an element. There is no fluorine in barium and not barium in fluorine.
A fluorine atom has 9 protons and 9 electrons, which are the defining features of an element.
The valency of fluorine is -1.
Fluorine seems a likely answer
Fluorine.