1. Bellringer/5.1 Notes 1.Name some similarities between the molecules of H 2 O and CO 2. 2. How are the molecules different? Study the models of the water molecule, H 2 O, and the carbon dioxide molecule, CO 2, and then answer the item below.

2. I. What are Compounds? A.Compound – The attractive force between atoms or ions When one or more elements combine to form a new substance 1.Chemical Bond – B. Compounds always have the same chemical formula 1.Chemical formulas tell us two things: a.Elements that make up the compound b. Ratio of elements that make up the compound

3. Example: C 12 H 22 O 12 C – Carbon:12 atoms H – Hydrogen:22 atoms O – Oxygen:12 atoms C. Chemical Structure –The physical structure of the compound 1.Structure determines a compound’s properties 2. Chemical structure shows things like bond length and bond angle

4. 3. Chemical structure also determines physical properties such as boiling and melting point D. Bond strength also varies and will determine physical properties 1. Some molecules are strongly attracted to each other while others are not Example: O 2 Oxygen forms a bond with another oxygen atom. However, these molecules do not form bonds with other O 2 molecules. This type of molecule is called a diatomic molecule.

5. E. Water forms hydrogen bonds 1.A hydrogen bond is a weak bond formed between water molecules