Turning our attention to layers doped with atoms from groups 13-15, we observe a general decrease in adsorption strength for higher periods. The exception is the second period, were the the the effects of doping deviate from the trend, likely for different reasons. Boron, in particular, facilitates the strongest adsorption with a significantly larger E ads compared to other dopants in the p-block. This discrepancy is large enough to suggest the presence of unique effects specific to this case. In contrast, both carbon and nitrogen exhibit weaker adsorption strength than their third-period neighbors, marking them as outliers within their respective groups. These atoms are among the smallest dopants studied, with covalent radii of 0.77 and 0.75 Å for carbon and nitrogen, respectively. This in combination with the structural constraints imposed by the sheet impedes their ability to adopt sp 3 -like hybridization. Their deep placement in the monolayer, as illustrated in Figure , indicates that the dopants minimize energy by adopting more in-plane bonding configurations, needed to reduce the length of the X-Mo bonds. This behavior, on one hand, diminishes the geometric availability of the adsorption site due to electrostatic repulsion from neighboring Te atoms. On the other hand, it limits the favorability of sp 3 hybrids in the dopants, necessary for accommodating strong binding with the adsorbed molecule. In comparison, Si and P, the subsequent elements in these groups, possess larger covalent radii and relax higher within the monolayer. This results in much stronger adsorption, driven by improved geometric availability of the adsorption site and the ability of the dopants to better accommodate an out-of-plane bonding configuration. After the adsorption of O 2 , the Si atom moves up by approximately ≈ 0.4 Å, indicating a shift in hybridization in the dopant towards sp 3 . This effect is not as pronounced for phosphorus, as it has one more electron in its valence shell than Si and is thus more inclined to adopt sp 3 -like hybrids on its own. Consequently, both dopants exhibit a similar value of ∆h X-Te upon the adsorption of O 2 .