Answer:
Chlorine is a very reactive non metals because this element don't form any known chemical compound.
Explanation:
Chlorine atoms have a lot of valance electrons without being complete on its own, so it has a greater need to seek it's conjugates. That's called electronegativity. Halogens are highly reactive because of their electronegativity.
If ice is warmed and becomes a liquid, the process is endothermic.
The process requires heat in order to proceed. If ice stays in a very cold place, it will not melt unless it's heated. If ice is placed outside where it melts on its own, it gets the heat from the surroundings.