Mechanical, because the other two make no sense and mechanical energy is the combination of kinetic and potential energy, or moving and still respectively.
Reactivity of Group 1 and 2 elements increases as you go down the periodic table. So sodium is more reactive than lithium. Sodium will react with oxygen forming Na2O (sodium oxide). Lithium forms lithium oxide (Li2O).
The temperature is the same but the heat flow is the opposite.
Answer:
what would the question be?
