in the stable form of protein, what is generally oriented to the interior of the protein molecule?

In the stable form of a protein, the hydrophobic portions (nonpolar side chains of amino acids) are generally oriented toward the interior of the protein molecule.

This happens because nonpolar, water-fearing side chains cluster inside the protein to avoid contact with the surrounding watery environment, while polar and charged, water-loving parts stay on the outside where they can interact with water.