A certain type of ship has two tanks in its engine. Each tank contains a different type of fuel. When the engine turns on, the same amount of energy is transferred out of both fuels as shown in the diagram below. Why did fuel 1 change phase, but fuel 2 stayed the same? Explain what happened to the molecules of both fuels.

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