An atom of calcium becomes a cation when it forms an ionic bond with two atoms of chlorine. What is the charge on the calcium ion? A. 1+
B. 2+
C. 3+
D. 4+

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.