Metalloids: A dividing line between metals and non-metals (PERIODIC TABLE #5)

On a standard periodic table METALLOIDS can be found in a diagonal region of the p-block, extending from boron at one end to astatine at the other.  Metalloids have properties of both metals and non-metals. Some of the metalloids, such as silicon and germanium, are semi-conductors. This means that they can carry an electrical charge under special conditions. This property makes metalloids useful in computers and calculators
The Metalloids are:

  • Six commonly recognised metalloids : boron, silicon, germanium, arsenic, antimony and tellurium.
  •  Elements less commonly recognised as metalloids include carbon, aluminium, selenium, polonium and astatine
              
1314151617
2B
Boron		C
Carbon		N
Nitrogen		O
Oxygen		F
Fluorine
3Al
Aluminium		Si
Silicon		P
Phosphorus		S
Sulfur		Cl
Chlorine
4Ga
Gallium		Ge
Germanium		As
Arsenic		Se
Selenium		Br
Bromine
5In
Indium		Sn
Tin		Sb
Antimony		Te
Tellurium		I
Iodine
6Tl
Thallium		Pb
Lead		Bi
Bismuth		Po
Polonium		At
Astatine
  Commonly recognised as a metalloid
  Inconsistently
  Less commonly
  Rarely

Typical metalloids have a metallic appearance but they are brittle and only fair conductors of electricity. Chemically, they mostly behave as (weak) nonmetals. They can form alloys with metals. Most of their other physical and chemical properties are intermediate in nature. Metalloids are usually too brittle to have any structural uses. They and their compounds are used in alloys, biological agents, flame retardants, glasses, optical storage, pyrotechnics,semiconductors and electronics. 
 Silicon is the second most abundant element in the Earth's crust after oxygen; tellurium is rarer than gold, but more abundant than rhenium, the rarest of the stable metals. Extraction can be achieved by ordinary chemical reduction of the oxides or sulfides.                                      
                                                   

INFORMATION CREDIT: wikipedia.org
                                            chemicalelemnts.com

IMAGE CREDIT: wikipedia.org

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