Z = 17 => K_2e L_8e M_7e => per 3, gr a VII-A, caracter nemetalic, caracter electrochimic electronegativ, valenta 1 ................... ... Z = 19 => K_2e L_8e M_8e N_1e => per 4, gr a I-A, caracter metalic, caracter electrochimic electropozitiv valenta 1