The table of the human essential elements consists of nearly two dozen items. This listing is top-most (Oxygen) to bottom-least (Chromium) elements. The table amounts are in both percentage and fraction. The last column has statements of what is essential about an item. The problematic aspect is the concentrations go down to parts-per-trillion. These low levels make assignments of essential elements questionable. The complete Molecular Elements Periodicity table is given at this hyperlink.