1. Table of Contents Title: Combining Matter (Bonds) Page #: 25 Date: 10/16/12

2. Objective Students will be able to describe the chemical bonds that unite atoms to form compounds. Students will be able to compare and contrast three different kinds of chemical bonds.

3. Words of the Day Ion - An atom with a net electric charge. Chemical Bond - The force that holds together the elements in a compound.

4. Combining Matter Covalent Bond - When two atoms are held together by sharing 1 or more electrons (atoms can only share their valence electrons.) e˜ Not bonded Bonded e˜

5. Combining Matter Molecule: Two or more atoms (they may be the same element) held together by covalent bonds. Molecules have no electric charge because the total number of protons matches the total number of electrons. Example: H O. O wants 2 electrons. Hs each want 1 electron. They all want to become stable! 2

6. Combining Matter Polar Molecule: When atoms in a molecule do not share electrons equally. Example: H O. Electrons are more strongly attracted to O atom than H atom. O becomes more negatively charged. H becomes more positively charged. + - + HH O 2

7. Combining Matter Ionic Bonds - Positive and negative ions attract each other. Example: NaCl. Made up of equal numbers of Na ions and Cl ions. Electric charge of NaCl is 0. + - Positive ion is always written first.

8. Combining Matter Ionic Compounds - Formed by ionic bonding. The number of positive and negative ions don’t always have to be equal, as long as the charge of the compound is 0 when ions are combined.

9. Combining Matter Metallic Bonds: In metals. Valence electrons are shared by all the atoms in a compound. A cluster of positively charged ions surrounded by freely moving valence electrons. Allows for the conduction of electricity. ++++ e˜

10. Classwork: Problem Solving Lab page 70. #1, 2, 3 only.