If i had an ionic molecule which needed 4 eV to break the ionic bond, a 7 eV photon is shot at it. It is absorbed by the molecule and breaks, where do the rest of the energy goes?
Breaking an (single) ionic bond is a nonsensical concept. Ionic bonding it the aggregation combination of many electrostatic interactions with a bulk solid. To liberate an ion from an ionic solid you have to break many bonds, not just one.
The energy can go to several different places:
1) The electrons may get some of the energy. In this case the dissociated atoms will be in excited states.
2) A photon might be emitted.
3) The atoms may have some kinetic energy left over after they are separated.