Where are metalloids located on the periodic table?

Where are metalloids located on the periodic table? Metalloids on the periodic table lie along the diagonal stair-step line between the metals and the nonmetals, in groups 13 to 16 of the p-block.

The six elements usually classed as metalloids (or semimetals) are boron, silicon, germanium, arsenic, antimony and tellurium, and some sources add polonium and astatine. Metalloids have properties between metals and nonmetals: they look metallic but are brittle, conduct electricity only moderately, and many behave as semiconductors, which is why silicon and germanium are used in computer chips and solar cells. Readers also ask “where are metals located on the periodic table”, which has its own short answer.

Their position follows the trend that metallic character falls from left to right across a period and rises down a group. The border is not sharp and different textbooks draw it differently, so the exact metalloid list varies. The same series of answers also covers “what is the most unreactive group on the periodic table”.

Metalloids are not a group (column) but a diagonal band that runs from boron in period 2 down to tellurium in period 5. The metalloids are boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb) and tellurium (Te). A separate page on this site answers “how many periods are in a periodic table”.

Silicon is the best known: it is the second most abundant element in the Earth's crust and the basis of microchips and glass. Boron is used in borosilicate glass and as boric acid, germanium in fiber optics and infrared lenses, arsenic in semiconductors, antimony in flame retardants and alloys, and tellurium in solar panels. Their electronegativity, ionization energy and electrical conductivity sit between those of metals and nonmetals, and the conductivity of a semiconductor rises with temperature, the opposite of a metal.

Because the boundary is gradual, sources disagree on borderline elements: polonium and astatine are placed with the metalloids in some tables and with the metals or halogens in others. Metalloids are also called semimetals, and they are found in phones, window glass and solar panels. Metals are located on the left of this line and nonmetals on the right side; you can find the line by locating boron and following the stairs down to tellurium.