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 answer is a

photosynthesis

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6