Endothermic because the separation of the ions dictate the overall reaction
The atomic number of calcium is 20 which means it has 20 protons and as an atom (not an ion) it also has 20 electrons. These are in four energy levels (1 though 4) .
At atmospheric pressure water boils at 100 degC.
So the water would be gas/vapor/steam.
If your science teacher says B, it’s probably because water has a negative and positive end, heat is just a form of energy, as other atoms can’t leave (they’re attracted to the ends) they are being insulated; but notice that ice will melt into gas (where atoms have tons of space) for other atoms to escape. Hence ice and gas aren’t ideal. (Air is a gas here.)
It’s not a 100% but hopefully it helps with some kind of analogy.
All the answers are on the actual periodic table. You should never be told to remember it so I think this is a recourse you are allowed to look at whilst doing your homework lol :) all the answers are written on it hope it helps
