To understand the deformation mechanism of each monolayer, we compute the variation of bond length as a function of strain. The 2D monolayers suffer geometrical changes due to tensile and compressive strain due to elongation and shrinking of bond lengths. There are two modes of strain loading that are physically meaningful for two-dimensional hexagonal symmetry, namely, uniaxial strain ( or ) and biaxial strain ( ). The strain is loaded by varying the lattice constants within the elastic range. The uniaxial and biaxial strains are applied from -5% to +12% at the step of 2% to investigate the influences on the bond length and thickness of the monolayer.