We will not use that system. The following information can be read directly from the periodic table. All other elements are naturally occuring elements. Our class wall table shows solid elements with black chemical symbols, liquid elements with blue chemical symbols, and gas elements with red chemical symbols. The dividing line begins between boron and aluminum and stair-steps down and to the right, one square at a time.
Metals are left of the line, nonmetals are to the right.
Metals increase in chemical activity as you go from right to left on a horizontal row and from top to bottom in a vertical column. Nonmetals increase in chemical activity as you go from left to right on a horizontal row and from bottom to top in a vertical column. The elements in the far right-hand column on the periodic table are chemically inert. Most of the families on the periodic table are in vertical columns. An element's oxidation number, sometimes called valence, is the number of electrons gained or lost by an atom when forming compounds.