What happens to the energy that is lost when water freezes

Water from a liquid state has internal energy in them that defines the translational and rotational energy of the molecules of water. However, when water freezes, it slowly turns into solid phase and therefore lesser temperature is applied to freeze the water molecules. The energy that is lost in the liquid is transferred to the solid state of the water. Even though there is little or no movement of water molecules in the solid state, there is still internal energy of the water. 

2. they have negligible mass.