  Optical beam shifts from a free-standing two-dimensional atomic crystal are
investigated. In contrast to a three-dimensional crystal the magnitude of the
Goos-H$\rm \ddot{a}$nchen shift depends on the surface susceptibility of the
crystal and not on the wavelength of the incident light beam. The surface
conductivity of the atomically thin crystal is less important in this context
because it enters in the expression of the shifts only as a second order
parameter. In analogy to a three-dimensional crystal the magnitudes of the
Imbert-Fedorov shift and of the angular shifts depend respectively on the
wavelength and on the square of the beam angular aperture.
