What is the full name of this element?

#"_9^19 X#

1 Answer
Sep 19, 2016

Answer:

This is atomic fluorine.

Explanation:

The #9# subscript is the atomic number for #""_9^19X#, and such an atomic number, #Z#, specfies the element fluorine. Most fluorine nuclei contain 10 neutrons, and thus the #""^19F# isotope predominates.

As the element, fluorine largely exists as the #F_2# molecule, which is the most reactive element on the Periodic Table.