Combining Elements Chapter 2

Compounds When two or more elements combine we get a compound. Examples are water and air. Salt or NaCl is also a compound

Types of Bonds When atoms combine they can attach themselves in one of three ways 1) Covalent Bond 2) Ionic Bond 3) Metallic Bond

Covalent Bond This occurs when an atoms outer electrons are shared with another atom Water is a more common example of this type of bond

Ionic Bond Atoms for this bond when they are electrically charged. A positive charged atom will bond with a negative charged atom such as a magnet

Metallic Bonds When metals bond they usually form metallic bonds. Electrons move freely between atoms and this is why metals conduct electricity so well

Mixtures Heterogeneous Occurs when two or more substances are mixed together, but each substance still looks the same. Sand and water is an example Homogeneous The substances are mixed together and you can’t see the individual substances. Mix sugar and water and the sugar dissolves. You’ve created a solution or a homogeneous mixture

Homogeneous vs. Heterogeneous

Today 9/25/07 Complete Atomic numbers, mass, and names review sheet We will play a DVD review game

Class Work Assignment Page 56 (Chapter 2 Review) Complete numbers 2, 6, 11, 12, 13, 14, 16, 17, 25, and 27

Tomorrow We will have a test over chapters 1 & 2. Look over the book, notes, and work handed back

Text Book Assignment General Science Page , 25 Page Pre-Chem Page 31 Vocab. 1-10, R.Q. 2,4,5,7,14, Ex. 11,13,14, Prob. 3,4