Why do sodium and cholesterol only cross the membrane by facilitated diffusion

Please help, I simply do not know. Thanks

Molecules requiring facilitated diffusion are ones that are either too polar, too ionic, or too large to pass directly through the membrane. These solutes/molecules require a facilitating channel to assist moving them down the energy gradient.

Cholesterol, for example, is non-polar. It is more stable when embedded in the non-polar interior of the phospholipid bilayer than when it is surrounded by the polar solvents inside and outside of the cell. It cannot directly diffuse through the membrane and needs to be diffused by a channel.

Sodium is too ionic to pass directly through the bilayer without going through the proper channels.