Which block is used to offset the periodic table ?
The following is the order for filling the " subshell " orbitals , according to the Aufbau principle , which also gives the linear order of the " blocks " ( as atomic number increases ) in the periodic table : 1s , 2s , 2p , 3s , 3p , 4s , 3 d , 4p , 5s , 4 d , 5p , 6s , 4f , 5 d , 6p , 7s , 5f , 6 d , 7p , ... For discussion of the nature of why the energies of the blocks naturally appear in this order in complex atoms , see atomic orbital and electron configuration .