A computer simulation model is presented to study the monolayer formation under conditions of diffusion controlled nucleation and growth in a linear electrode in contact with a bidimensional solution. The diffusion of the electroactive particles in the solution and on the electrode surface is described explicitly. This fact allows the study of the nucleation and growth phenomena without the need to impose analytical laws that would condition the behaviour of the system. The model is focused on the role of the diffusion process in the kinetics of the electrode surface coverage and in the spatial distribution of nuclei. Thus, no restrictions are imposed on the position where a nucleus may appear and on the overlap among growing nuclei. The temporal evolution of the number of nuclei and the rate of nuclear growth is analysed. The electrode surface coverage values yielded by the computer simulations differ by 5-20% from the Avrami theorem predictions due to a nea-random distribution of nuclei on the electrode surface as the g(r) internuclear pair correlation functions indicate. The electrode coverage follows a non-poissonian probability distribution which has been characterized. The correlation found among the g(r) curves, the rate of nuclear growth and the nucleation probability values permit the non-Avrami behaviour to be interpreted in terms of the depletion of electroactive particles and the appearance of zones of reduced nucleation around every growing nucleus. A nuclear deficiency parameter is defined to quantify the reduced nucleation zones. Finally, the influence of the surface diffusion on the coverage properties is also studied.