Chlorine to iodine
Considering the halogens from chlorine to iodine, it is the lattice enthalpy which has fallen most. It falls by 87 kJ mol-1. By contrast, the heat needed to remove the electron has only fallen by 54 kJ mol-1.
Shouldn't it be "has fallen the most"?
There are several characteristics, and one has fallen by the highest amount compared with the others.