Molecules that are optically active due to the tetrahedral arrangement of bonds around the carbon atom are often referred to as

             Molecules that are optically active due to the tetrahedral arrangement of bonds around the carbon atom are often referred to as Chiral Molecules.

Explanation:
                   Chiral molecules have stereogenic centers. When plane polarized light is fall on these compounds they rotate the light either in clockwise or anti clockwise direction. The mirror images of chiral moleculecules are non-superimposable.  Below few examples for molecules containing chiral centers are given.