The IB defines lattice enthalpy as the enthalpy change when one mole of solid ionic compound is broken up into gaseous ions, so it is correct. It can also be defined as the opposite process so it depends on which definition you use.
Hello Mr Jones. I did not understand this question, it is from a past paper. I don't know how to determine which one is arranged in the correct order even if I tried to find the reason, do you mind if you explain it to me? Here is the question: 18. What is the order of increasing (more exothermic) enthalpy of hydration? Xn+ (g) → Xn+ (aq) A. Ca2+, Mg2+, K+, Na+ B. Na+, K+, Mg2+, Ca2+ C. K+, Na+, Ca2+, Mg2+ D. Mg2+, Ca2+, Na+, K+ It was a hard question so I would appreciate if you help me.
Smaller ions with a higher charge have higher delta H of hydration. So the ion with a smallest ionic radius and highest charge has the highest value (Mg2+).
