Chapter 4 Elements, Compounds & Mixtures Warning; the test for this chapter is one of the toughest.

Chapter 4

Elements, Compounds & Mixtures

Warning; the test for this chapter is one of the toughest

Section 1 - Elements

I. ELEMENTS (p.82-85) -An element is a pure substance that cannot be separated into simpler substances by physical or chemical means.

Gold

iodine

http://www.lighthouse.chtr.k12.ma.us/periodic/periodicimages/iodine.jpg www.zyra.org.uk/ mercury3.htm

Mercury

http://mineral.galleries.com/minerals/elements/gold/gold.htm

A. An element has only one type of particle. 1. A pure substance is a substance that has only one type of particle. 2. For example every particle (atom) in a 5 g nugget of the element gold is exactly like every other atom of gold in the nugget.

http://www.uni-ulm.de/fkp/hilights/sep2002/bild2.gif

Every element can be found on the periodic table. If it’s not on the table on page 744. it’s not an element.Is aluminum an element?steel?oxygen?carbon dioxide?Fluoride?

Section 1 - Elements

1. Each element has it's own characteristic properties.

a. These properties do not depend on how much of the element is present.

b. Examples of characteristic properties include, boiling pt., melting pt. density and reactivity with acid.

B. Every element has a unique set of properties that allow you to identify it. ( Can you remember 6 of the 9 properties listed here?)

http://www.astro.su.se/~magnusg/large/Boiling_water.jpg

Section 1 - Elements

Even properties like flammability, reactive with oxygen and other unusual characteristics can be used. (These properties are not physical properties)

2. We identify elements by their properties. Physical properties such as color, hardness, and texture can also be used.

Calcite- a rock that contains calcium compounds will glow under a “black light”

http://disc.gsfc.nasa.gov/oceancolor/images/fluorescent_calcite_willemite.jpg

Section 1 - Elements

C. Elements are categorized by their properties. 1. Elements are categorized into groups based on their shared properties. For example Iron nickel and cobalt are all shiny, conduct thermal energy, and electric current. So they are categorized as metals. Metals are not all exactly alike but they have enough in common to be in the same group.(Most elements are metals) (Types of elements overhead)

metals movie clip

Section 1 – Elements

2. If you know what category an element belongs to you can predict the properties.

a. Metals- shiny, good conductors of heat and electric current, they are malleable

(hammered into thin sheets), and ductile (drawn into thin wire).

http://www.volcanoarts.biz/cart/wire/20ga-wire.jpg

Section 1 - Elements

b. Nonmetals- Dull (not shiny), poor

conductors of heat and electric current,

solid non metals are brittle (broken easily) and

unmalleable. Many are gases.

( They are mostly found on the right side of the periodic table. There are only 17)

Non-metals clip

Section 1 - Elements

c. Metalloids- (also called semiconductors) is elements that have properties of both metals and non-metals. Some are shiny while others are dull, they can be somewhat malleable and ductile. Some conduct thermal energy (heat) and electric current. (There are only 8 metaloids)http://www.quigmans.com/elements.swfMetalloid movie clip