Definition Of Metalloids

Definition Of Metalloids

The elements which possess the character of both metals and non – metals are called as metalloids

More About Metalloids

  • The metalloids or semimetals are located along the line between the metals and nonmetals in the periodic table
  • The metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium
  • Other elements less commonly recognized as metalloids include carbon, aluminium, selenium, polonium and astatine
  • The electronegativities and ionization energies of the metalloids are between those of the metals and nonmetals
  • The metalloids exhibit characteristics of both classes
  • Silicon, possesses a metallic luster, yet it is an inefficient conductor and is brittle
  • The reactivity of the metalloids depends on the element with which they are reacting
  • Boron acts as a nonmetal when reacting with sodium yet as a metal when reacting with fluorine
  • The boiling points, melting points, and densities of the metalloids vary widely
  • The intermediate conductivity of metalloids means they make good semiconductors
  • On a periodic table all of these elements can be found in or near a diagonal region of the p-block
  • Chemically, they mostly behave as weak nonmetals
  • They can, however, form alloys with metals.
  • Some properties of metalloids are
  • Electronegativities between those of metals and nonmetals
  • Ionization energies between those of metals and nonmetals
  • Possess some characteristics of metals/some of nonmetals
  • Reactivity depends on properties of other elements in reaction
  • Often make good semiconductors
  • Metalloids generally form amphoteric oxides
  • Some allotropes of elements exhibit more pronounced metal, metalloid or non-metal behavior than others
  • For example, for the element carbon, its diamond allotrope is a non metal and graphite allotrope displays limited electrical conductivity which is a more characteristic of a metalloid
  • Phosphorus, selenium, tin, and bismuth also have allotropes that display borderline behavior

Uses of Metalloids:

  • All the elements commonly recognized as metalloids (or their compounds) have found application in the semiconductor or solid-state electronic industries
  • Arsenic has been used as a pharmaceutical agent since antiquity and notably for the treatment of syphilis prior to the development of antibiotics
  • Compounds of antimony are used as ant protozoan drugs, and in some veterinary preparations
  • Boron is used in insecticides and herbicides. It is a trace element. As boric acid, it also has antiseptic, antifungal, and antiviral properties
  • Silicon can be applied to badly burned patients, in the form a silicone gel, to reduce scarring
  • Tellurium is not an essential element. Tellurium dioxide has been used to treat seborrhea dermatitis
  • lead arsenate, has been extensively used as an insecticide