The atomic orbital wave functions were obtained with SCF calculation. Integrating their square over angle

the atomic radial density functions were obtained. Then

the total atomic radial density function was calculated by adding the radial density functions of those atoms whose orbits were occupied. The atomic orbital exponents were obtained by fitting the total atomic radial density function with the basic functions obtained from integration of the squared orbits of hydrogen like atoms over angle. All the atomic orbital exponents and orbital radius of the 3rd period elements were calculated in this paper.