Fluorine (a halogen) is because it has
outer shell electrons.
A. Slightly Reactive, 9
B. Very Reactive, 7
C. Very Reactive, 1
D. Inert, 7

The correct answer would be B.

Fluorine (a halogen) is very reactive because it has 7  outer shell electrons.

Explanation:

It's located at the top of the Halogen Group in the periodic table and it's the most electronegative element, this makes it very reactive.

I hope this helps you:)

c is the answer because when something is left after something evaporates that shows the chemical change.

distance, luminosity, brightness, radius, chemical composition, and temperature