Final answer:
The ionic end of a soap molecule that is attracted to water is called the hydrophilic head. Soap molecules are amphipathic, with both hydrophilic and hydrophobic regions, allowing them to emulsify fats and oils in water.
Step-by-step explanation:
In relation to water solubility, the name given to the ionic end of a soap molecule that is attracted to water is known as the hydrophilic head. This hydrophilic head is capable of dissolving in water due to its affinity for water molecules. The opposite end, which repels water, is called the hydrophobic tail. These two distinct regions make the soap molecule an amphipathic molecule, which means it has both a hydrophilic (water-loving) and a hydrophobic (water-fearing) part.
When soap is added to water, the hydrophilic head is drawn to the water and dissolves, while the hydrophobic tail repels water. In a micelle formation, the soap molecules arrange themselves such that their hydrophilic heads face outward towards the water, and their hydrophobic tails are tucked away from the water, trapped in the interior. This structure allows soap to emulsify lipids, fats, and oils, which can then be washed away.