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ONMETALS AND

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ETALLOIDS

Chapter 1, Unit 4 Tuesday, September 11, 2012

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OMETHING TO THINK ABOUT

…    Which elements in the periodic table are nonmetals and which are metalloids?

What properties identify nonmetals? What properties identify metalloids?

Describe an important use of metalloids?

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HAT IS A NONMETAL

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   Nonmetals are elements that lack most of the properties of metals.

 Positioned to the right of the zig zag line.

Many nonmetals are very common and extremely important to all living things on Earth.

Physical Properties   Gases at room temperature.

 Low boiling points Carbon and Iodine-solid at room temperature    Bromine-liquid at room temperature Physical properties of nonmetals are opposite to those of metals Poor conductors of heat and electricity

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HAT IS A NONMETAL

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 Chemical properties   Most nonmetals readily form compounds.

 Group 18 is the exception All other nonmetals have atoms, leading to the formation of bonds and compounds.

 Compounds of nonmetals   Nonmetals and metals Nonmetals and nonmetals  Atoms share electrons and combine into molecules  Molecules with only two (2) atoms are called DIATOMIC MOLECULES

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AMILIES OF NONMETALS

  Carbon Family      Group 14 Only nonmetal-Carbon Silicon and germanium are metalloids Tin and lead are metals ALL LIVING THINGS HAVE AND NEED CARBON TO SURVIVE!!!

Nitrogen Family   Group 15 2 nonmetals-nitrogen and phosphorous   Air is almost 80% nitrogen Nitrogen is used in fertilizers    Phosphorous is not a stable element Always found in compounds Used to make matches and flares because of its reactiveness.

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AMILIES OF NONMETALS

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 Oxygen Family   Group 16 3 nonmetals-oxygen, sulfur, and a rare element selenium     Oxygen travels all throughout the body via the lungs and bloodstream.

Oxygen is also prevalent in the ozone layer Very reactive and can combine with almost every other element Sulfur has an unpleasant, rotten egg odor.  Found in rubber bands, automobile tires, and many medicines

FAMILIES OF NONMETALS

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   Halogen Family  Group 17       Fluorine, chlorine, bromine, iodine, and astatine “Halogen” means salt-forming 1 nonmetal-Fluorine Physical states of Group 17 elements vary Very reactive and most are dangerous to humans Some have many helpful uses.  Look these up on your own!!!

Noble Gases  Group 18   Do not ordinarily form compounds with other elements  Reason: atoms of noble gases are chemically very stable and unreactive All exist in Earth’s atmosphere in small amounts Hydrogen   Top left corner Most simplest element    Cannot be grouped into a family because its chemical properties are so different.

Makes up 90% of atoms in universe. Rarely found on earth in an uncombined form.

 Commonly found with oxygen in water

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ETALLOIDS

  Seven elements on the periodic table between the metals and nonmetals Most useful property of the metalloids is their varying ability to conduct electricity   Depends on temperature, exposure to light, or presence of small amounts of impurities Some are used to make semiconductors   Substances under some conditions can conduct electricity (like a metal) while under other conditions cannot conduct electricity (like a nonmetal).

Used to make computer chips, transistors, and lasers

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OMETHING TO THINK ABOUT

…   Which elements in the periodic table are nonmetals and which are metalloids?

  Nonmetals-carbon, nitrogen, phosphorous, oxygen, sulfur, selenium, fluorine Metalloids- Boron, silicon, arsenic, tellurium, astatine, germanium, antimony What properties identify nonmetals? Which properties identify metalloids?

  Nonmetal properties-gas at room temperature, dull, brittle if solid (not malleable) Metalloid properties-gas or solid, shiny or dull, malleable or non-malleable.

 Describe an important use of metalloids.

  Their varying ability to conduct electricity Also used in making computer chips, transistors, and lasers.