melting - 

changing from solid to liquid

evaporation - 

changing from liquid to gas

condensation - 

changing from gas to liquid

freezing - 

changing from liquid to solid

sublimation - 

changing from solid to gas

fluorine - 

F

chlorine - 

Cl

bromine - 

Br

iodine - 

I

astatine - 

At

volatility - 

The tendency of a substance to evaporate.

sublimation - 

The process of changing state from solid to gas with no liquid phase.

displacement - 

When a more reactive element pushes a less reactive element out of a compound.

melting point - 

The temperature at which a solid changes to a liquid.