Just one, Fluorine. To dig a little deeper, Fluorine exists as F2 (g).
there are 5 atoms douse fluorine
The stable isotope, Fluorine-19, has 10 neutrons.
Fluorine's atomic number is 9.. That means it has 9 positively charged protons per atom. To keep it neutral then, it must also have 9 negatively charged electrons per atom.
9 electrons !
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