What property of elements is used to organize the periodic table?

There are many factors that go into how elements are arranged in the Periodic Table. The main factor is that they increase left to right by atomic number. Elements are also grouped by families (columns) and periods (rows). Elements of the same family have the same number of valence electrons and also will have similar properties. Certain families will thus bind well ith each other while others will not. Though not organized as so, Atomic Mass usually increases with atmic number, but there are some exceptions to this.