Transcript Chapter 4
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. Mercury iodine Gold http://mineral.galleries.com/minerals/elements/gold/gold.htm http://www.lighthouse.chtr.k12.ma.us/periodic/periodicimages/iodine.jpg www.zyra.org.uk/ mercury3.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 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?) 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. http://www.astro.su.se/~magnusg/large/Boiling_water.jpg Section 1 - Elements 2. We identify elements by their properties. Physical properties such as color, hardness, and texture can also be used. Even properties like flammability, reactive with oxygen and other unusual characteristics can be used. (These properties are not physical properties) Calcite- a rock that contains calcium compounds will glow under a “black light” 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) 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). 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.swf Metalloid movie clip