The study of the lateral distribution of electrons in an atmospheric cascade can lead to useful conclusions on the mass and energy of the primary cosmic particle. In this work we compare the results we get from simulations by the CORSIKA program, with the theoretical NKG function expressing the lateral distribution of electrons. We then modify the original NKG function to fit better the data of the simulation. Finally, we propose this procedure as a method to approach the mass of the primary particle which started the atmospheric cascade.