Answer:
Because it has a darker pigment?
Explanation:
The element that has a complete valence electron shell is argon (Ar) since it is a noble gas in the last group on the periodic table.
I'm pretty certain the answer is 2) because fluorine is a diatomic gas meaning it travels with 2 molecules (simplified). It is a gas so molecules should also be spread out so the answer cannot be 3) or 4).
Hope this helps! :)
1 moles lithium or 6.941 grams