The cycloadditions of 21 singlet substituted carbenes, silylenes, and germylenes onto the diamond ( 100) surface have been theoretically studied by means of density functional theory coupled with effective cluster models. The calculated reaction energies and reaction pathways have disclosed that the substituents play an important effect on the reaction profiles for the additions of carbenes, silylenes, and germylenes onto the diamond ( 100) surface. Our theoretical investigations illustrate that, irrespective of carbenes, silylenes, and germylenes, the cycloadditions of those with electropositive substituents ( such as H and CH3) onto diamond ( 100) are much more favorable than those with electronegative and pi-donating substituents ( such as F and NH2) both thermodynamically and kinetically. In broad perspective, we believe that a similar reactivity trend can also be extended to that of Si ( 100), Ge ( 100), fullerene, single-walled carbon nanotube, disilenes, digermenes, silenes, and germenes because all of these materials feature an analogous bonding motif.