Solid sodium is reacted with chlorine gas and a crystalline solid was formed. The crystalline solid is evidence that A. The sodium was broken down into tiny pieces by the chlorine.
B. The reaction caused impurities to fall out.
C. Elements bond in a multitude of ways to make compounds.
D. The chlorine solidified.

C. Elements bond in a multitude of ways to make compounds.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.