1 Metalloids

2 Properties of Metalloids Semiconductors Have properties of both metals and nonmetals Usually shiny Brittle

3 Metalloids include Boron Silicon Germanium Arsenic Antimony Tellurium Polonium Astatine

B ORON Chemical Symbol- B Atomic number- 5 Atomic Mass- 10 to 11 Density-2.35 g/cm³ Melting Point- 2360ºC(4170ºF) Boiling Point- 2550ºC(4620ºF) Solid at 25ºC(77ºF) 4

H ISTORY Discovered in 1808 by Joseph Louis Gay-Lussac and Louis Jacques Thenard in Paris, France and Humphrey Davy in London, England Comes from borax, a compound made from boron, which dates back 600 years in old England and even back to Arabic and Persian 5 Gay-LussacThenardDavy

F ACTS essential to plants Toxic intake- 5g (boric acid lethal intake- 10 to 20g (boric acid) Abundances in the Sun, Earth’s Crust, Seawater it is nature made with about 10 g/ton on earth 6

U SES Glass is a compound which contains Boric acid Some boron compounds are used to make ceramics Used as an extinguisher in forest fires by smothering the flames and coating the trunks and branches to make them fireproof. 7

B IBLIOGRAPHY Beatty, Richard. Boron. Tarrytown, NY: Marshall Cavendish cooperation, Emsley, John. The Elements. Oxford, New York: Oxford University Press,

SILICON, METALLOIDS 9

10 ORIGIN OF THE NAME OF THE ELEMENT SILICON. The origin of the name of the name of the element silicon comes from the Latin word “ silex” meaning “ flint”. Silicon has 14 protons and electrons. Silicon was nature made. Discovered in 1823 by Jons Berzelius Silicon is mainly used in computer chips, solar cells, and transistors. Found in clay, granite, quartz, and sand.

11 INTERESTING FACTS. Metalloids form a diagonal line on the table, rather than a vertical line Silicon is one of the most important metals used to make electronics. Arsenic is known to be one of the most poisonous of elements. Tellurium gets its name from the Latin word "tellus" which also means "earth."! Antimony gets its name from the Greek words "anti monos" also meaning "not alone."!

Lets take a look at all of the Metalloids! 12

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18 ments/si Book: benchmark books- the elements- silicon

TELLURIUM o Chemical symbol: Te o Atomic number: 52 o Color: silver-gray o Density: g/cm³ o Melting point: ˚c o Boiling point: 988˚c 19

Tellurium Tellurium was discovered in Romania in 1783 by Franz Muller von Reichenstein The word Tellurium comes from the Greek word tellus which means Earth 20

Tellurium o Used as a semiconductor o Used to color glass and ceramics o Used as an alloying agent o Small amounts added to copper and stainless steel o Added to lead to increase strength and resistance to sulfuric acid 21

Tellurium Tellurium has a shiny silver-gray color Tellurium is very brittle and can be smashed into a powder 22

Tellurium Facts o The element is toxic to handle o There are thirty know isotopes of tellurium o It has 52 protons and electrons o Tellurium has 76 neutrons o It burns in air or oxygen o It is unaffected by water o Tellurium is found in Australia, USA, and Romania 23

Bibliography Dingle, Adrian. The Periodic Table. Boston: King Fisher, 2007 Emsley, John. The Elements. Oxford, New York: Oxford University Press,

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