Any element, other than a halogen is - by definition - not a halogen and so it does not have a halogen and that is less than one halogen.
Astatine
Francium. Oh, and you spell it Halogen :)
it is called a halide.
No halogen gas has a mass of under 15 atomic mass units. The closest is fluorine, at 19.0 atomic mass units.
Fluorine, at 19 atomic mass units, is the only halogen gas that fits that requirement.
A halide is a compound consisting of two parts; a halogen and another electronegative element. The mostcommonhalogens arefluorine(F),chlorine(Cl),bromine(Br),iodine(I), andastatine(At). If put together with another element, they formfluoride,chloride,bromide,iodide, orastatide. Therefore, your question is not right since a halide consist of elements and one element can only be a halogen or non-halogen. (halogen and halide are two different things)
The rarest element on earth is astatine and it is located in the earths crust. Astatine's availability is said to be less than a gram in weight.
alkaline earth metals
The more reactive it is the more less likely it is to be found in pure form
Less than one ounce of astatine exists on Earth. It was discovered by D.R. Corson, K.R. MacKenzie and E. Segre in 1940.
In the earth Astatine is rarest naturally occurring element, less than 30 grams for entire crust.
no