The geometries, electronic structures, and magnetic properties of H-, B-, C-, N-, O-, and F-absorbed monolayers have been investigated by first-principles calculations. The results demonstrate that all these atoms can chemically absorb on monolayer. The total magnetic moments of H-, B-, C-, N-, and F-absorbed monolayers are 1.0, 1.0, 2.0, 1.0, and , respectively. The large spatial extensions of spin density and long-range antiferromagnetic coupling were observed in H- and F-absorbed monolayers. Additionally, the -type and -type two-dimensional semiconductors can be realized by absorbing H and N atoms, respectively.