Answer:
The enthalpy of an endothermic reaction is positive, I believe.
a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
Your hypothesis is at the biggenning or the end of you summary
The answer would be freezing
An example is when on a seesaw if a kid is on one side and an adult is on the other then it is unbalanced because the adult weighs more
