This is the Extended Standard Periodic Table. It is also arranged according to Increasing Atomic Number. The elements fall into groups that have similar properties, but we can see how the Lanthanide and Actinide series of elements fit into the Standard Periodic Table. A common question from Students about the Standard Periodic Table is, “Why is the Lanthanide and Actinide series separated from the rest of the Table?” The answer is simply one of efficiency of both economics and space. Less paper to produce a larger table.