Where's the list? It depends on which one it is. It could be Chlorine, silicon, or anything on the non metals side of the periodic table if you don't list it.
To calculate an electron configuration, divide the periodic table into sections to represent the atomic orbitals, the regions where electrons are contained. Groups one and two are the s-block, three through 12 represent the d-block, 13 to 18 are the p-block and the two rows at the bottom are the f-block.
