The structural stability of some two-dimensional materials at ambient conditions is obviously attributed to their low sensitivity to exposure of humidity and air. Recently exfoliated antimonene, differently from another group-VA material, phosphorene, possesses a high structural integrity at ambient conditions. Considering the kinship of phosphorene and antimonene, there is a need to comprehensively examine the interaction of the H2O and O-2 molecules with the antimonene surface to understand the difference in the structural stability of these materials. The calculations predict that antimonene, similarly to phosphorene, shows higher affinity to oxygen rather than water. Surprisingly, for antimonene, the barrier for the O-O bond splitting to form O-Sb bonds is found to be much lower than that of for phosphorene. However, antimonene, in contrast to phosphorene, preserves structural integrity upon oxidation which may be attributed to a stronger interaction and hybridization of atoms in antimonene compared to the atoms in phosphorene. In addition, the oxidation ability of antimonene can be significantly controlled by the graphene and BN substrates.