The Lewis electron dot diagrams for CO2 and SO2 are given belowThe molecular geometry and polarity of the two substances are

Both the C–O and S–O bonds are polar due to the different electro negativities of the bonded atoms. However the CO2 molecule is linear and non polar due to the cancellation of the bond dipoles. In SO2 the molecule is bent and the bond dipole do not cancel. The polarities of the two substances differ because of the differences in geometries. This is a consequence of number electron domains around the central atom, 2 in CO2 and 3 in SO2.