CH 4 Earth Chemistry

Section 4.1 Matter is anything that takes up space and has mass. An element is a substance that cannot be broken down into simpler, stable substances. Most common elements in Earth’s crust: Oxygen 46.6% Silicon 27.7% Aluminum 8.1% Also Iron, Calcium, Sodium, Potassium, Magnesium, others

Isotopes Atoms with the same number of protons and electrons, but different numbers of neutrons Only Atomic Mass changes

Periodic Table Go to Pg 86 How is Atomic Mass Calculated? Based on the isotopes that have different masses, the Periodic Table uses the average of the different masses for each element.

Practice Drawing Atoms What does the atom of Oxygen look like? What does the atom for Lithium look like? What does the atom for Boron look like?

Why are the outer shell electrons important? These are the electrons that are used for reactions! The outermost electrons are able to react with other atoms Also Opposites attract Let’s Identify the Valence Electrons for the groups of the Periodic Table

Ions Charged Atoms-Allow the atoms of the elements to react Examples……. Na+ + Cl-  NaCl Al 3+ + O 2-  Al2O3 Opposites Attract!!!

Types of Bonds Covalent Bonds-A bond that is formed by the attraction between atoms that share electrons. Very strong Bond Ionic Bonds- The attractive force between oppositely charged ions that results from the transfer of electrons from one atom to another Very weak bond

Types of Bonds Polar Covalent Bonds-In between an ionic and covalent bond- a Bond that does not equally share electrons and therefore creates a polar bond

Mixtures Elements and compounds are generally mixed together. A mixture is a combination of two or more substances that are not chemically combined. Heterogeneous Mixture- mixture that is not uniformly distributed. Homogeneous Mixture- mixture that is uniformly distributed. IE a solution of Salt water.

Chapter 5 Minerals Know the four criteria for minerals. Explain what a silicon-oxygen tetrahedron is and the different arrangements. Know the seven properties of minerals that help us identify them and be able to explain how to find hardness.

Minerals Examples Rubies Gold Nugget Salt A mineral is a natural, usually inorganic solid that has a characteristic chemical composition, an orderly internal structure, and a characteristic set of physical properties.

Minerals in Chihuahua

http://channel.nationalgeographic.com/episode/Videos/08822_00

Characteristics of Minerals Is it inorganic? Not made out of previously living things Does it occur naturally? Things made in nature not a lab Is it crystalline solid? Has a regular repeating crystalline structure Does it have a consistent chemical composition A common chemical formula Pg 103

Properties of a Mineral Color Streak Luster Cleavage and Fracture Hardness Crystal Shape Density

Read pg 109-112 Create notes or an graphic organizer explaining in detail the 7 main properties of minerals. For bonus you can take notes or continue your graphic organizer on the Special Properties of Minerals from page 113 -114