What can be predicted by using the periodic table?

While some trends in the periodic table can hint at common charges for certain groups of elements (like alkali metals and alkaline earth metals), it does not directly provide the charges of polyatomic ions. Polyatomic ions consist of multiple atoms bonded together, and their charges are determined by the specific combinations of elements and their bonding rather than a direct reference to the periodic table.

The periodic table does not indicate the number of isotopes for each element. Isotope information is a separate aspect of an element's nuclear chemistry, which is not represented in the table's arrangement. The number of isotopes varies among elements and is not a predictable property based solely on their periodic placement.

Although the periodic table can suggest gaps in elemental properties that hint at the potential for undiscovered elements, it cannot predict their discovery. The existence of new elements is contingent upon experimental verification and synthesis, which cannot be forecasted solely from the periodic arrangement.