Hi

the basic outline of what we are planning to present

Definitions

Metalloids: an element with both the properties of metals and nonmetals

semiconductor: a substance that has an electrical conductivity depending on the temperature, exposure to light, or presence of small amount of impurities

Names of Metalloids

B-Boron

Si-Silicon

Ge-Germanium

As-Arsenic

Te-Tellurium

At-Astatine

Note: There are a few more that other sources recognize.

__Physical Properties of Metalloids__

because the properties of metalloids vary so much depending on each case, it is really hard to make a generalization. However, these are some common properties that all metalloids have:

1. Brittle
2. behave as an electrical insulators at room temperature but become electrical conductors when heated or when small quantities of certain elements are mixed together
3. good conductors of heat and electricity, but not as well as metals
4. solids
5. ductile
6. malleable

Chemical Properties of Metalloids

1. have nearly empty outer electron shells of typical metals, and the nearly filled electron shells of the nonmetals

1. have enough empty electron orbital into which electrons can be moved to conduct elecctric current

1. usually forms alloys with metals (ex. Iron, Copper, Carbon)

#have enough empty electron orbital into which electrons can be moved to conduct electric current

Application to Daily Life

Metalloids are important industrial materials. Generally used for:

1. transistor
2. semiconductor devices
3. ceramics
4. solar batteries

Boron-boron filaments are used in the aerospace industry because of their high strength and lightweight.

Silicon-silicon carbide is nearly as hard as diamond and is used as an abrasive

Germanium-Used to create alloys and also as a phosphor in fluorescent lamps

Arsenic-used to make rat poison and some insecticides. also used to chronic poisoning of people you don't like.

Tellurium-tellurium is also added to lead to increase its strength and resistance to sulfuric acid.

__Interesting Facts__

-boron compounds can kill in a matter of seconds if contacted with bare skin

-silicon is the seventh most abundant element on earth and second most abundant element in earth's crust

-telluerium forms many compounds, but none of them are commercially important

-the total amount of astatine in the earth's crust at any particular time is less than thirty grams

-Some historians believe Napoleon Bonaparte is chronically poisoned by arsenic

-arsenic's boiling point is lower than its melting point, because these two temperatures are measured at different atmospheric pressures.

links & sources

www.wwnorton.com

www.lenntech.com

www.answers.com

web.buddyproject.org

------------------------------------------------------------------------feb22.06-----

here are some interesting facts about semi metals(Metalloid)

--Metalloids have electronic structures intermediate between the nearly empty outer electron shells of the typical metals and the nearly filled electron shells of the nonmetals.

--depending on temperature, exposure to light, or presence of small amount of impurities, semi metals can either conduct or insulate electricity/heat (meaning semi metals are semi conductors!!)

--Metalloids are important industrial materials. Used for:-transistors-semi conductor devices-ceramics-solar batteries

--Silicon(different from silicone)is an abundant element on earth, and it is used for

-glass

-cement

-ceramics

-most semiconductor devices

-constituent of major ingredients of steels

-constituent of major ingredients of bricks

-enamels

-Silicon chips are used in integrated circuits

well that's what i have for now...as 'interesting'. i will keep adding :)

-HaeBin, Liyan, and Alan

QUESTIONS!

#1. What are metalloids?

#2. How good are they at conducting heat and electricity?

#3. Name one of the chemical properties. (out of three)

#4. How many metalloids were introduced?

#5. Name one use of any one of the metalloids introduced.

-Liyan.