Locate the semimetals, which are also called metalloids, on the periodic table of elements. The elements boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and astatine (At) are metalloids. These elements have some characteristics similar to metals and also have characteristics similar to nonmetals.
Trace the semimetal line, if the table isn't color coded. First find the element boron (B), which is in the top row of the table. Draw a line shaped like a stair step that begins on the left side of boron and travels down the left side and across the bottom of boron. Continue drawing this stair step shaped line in the same pattern: down, left, down, left. Eventually the line will come to an end between polonium (Po) and astatine (At). Each element that shares a straight horizontal or vertical border with the staircase is a semimetal, with the exception of aluminum (Al) and polonium (Po).
Look at the elements on the left side of the periodic table. Every element that is located on the left side of the semimetal staircase line, except for the semimetals, is a metal. This means that if an element is clearly located on the left side of the table, it is a metal. If the version of the periodic table is color coded, notice that the elements on the the left side of the semimetal line are colored differently than those on the right. Keep in mind that the semimetals identified in Step 1 are separate from the metals, regardless of their shading.
Notice the elements on the right side of the periodic table. Nonmetals are located to the right of the semimetal staircase line, with the exclusion of the semimetals.