Position of Metals, Non-Metals and Metalloids

In order to locate the position of metals, non-metals and metalloids in the periodic table, you may draw a diagonal line joining the element boron (At. no. 5) with that of tellurium (At. no. 52) and passing through silicon and arsenic.

The elements above the diagonal line and to the far right are non-metals (except selenium which shows slightly metallic character also). The non-metallic character is more marked the farther an element is from the diagonal line and up.

The elements below the diagonal line and to the left are metals. Hydrogen is a non-metal and is an exception. The metallic character is more marked the farther an element is from the diagonal line and down. All lanthanoids and actinoids are metals.

The elements along the diagonal line are metalloids and possess the characteristics of metals as well as of non-metals. In addition germanium, antimony and selenium also show the characteristics of metalloids.