What happens when liquid changes to gas? 1.Added heat makes water molecules move fast enough to overcome the attraction
between them
2. Heat causes molecules to speed up and merge together (Which one?)

#1

The temperature that this happens is called the freezing point and is the same temperature as the melting point. As more energy is put into the system, the water heats up, the molecules begin moving faster and faster until there is finally enough energy in the system to totally overcome the attractive forces.

Explanation:

#2

Heating a liquid increases the speed of the molecules. An increase in the speed of the molecules competes with the attraction between molecules and causes molecules to move a little further apart. ... A decrease in the speed of the molecules allows the attractions between molecules to bring them a little closer together.

answer; /// i do believe that the correct answer is (a) boiling

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.