1.  Objective: To describe how atoms bond together to form compounds using valence electrons  Journal: ◦ How many protons, neutrons and electrons are in gold? ◦ Atomic # - 79 ◦ Atomic Weight - 197

3.  A substance composed of two or more elements that are combined  Combined using chemical bonds

4.  The number of electrons in the outer shell.  Used for bonding

5.  When bonding, each atom wants to have a full outer shell (8 valance electrons)  ***Exception is Hydrogen, which can only hold two electrons in its outer shell

6.  Ionic Bonds  Covalent Bonds  Hydrogen Bonds

7.  When bonds form between atoms by either gaining or losing electrons ◦ Results in the compound having either a positive or negative charge

8.  When an atom has an electrical charge it is called an ion ◦ If an atom gains an electron it has a negative charge ◦ If an atom loses an electron it has a positive charge

9.  When bonds form between atoms by sharing valence electrons

10.  When a hydrogen atom has a partial positive charge that is very strong it attracts to the negative charge of specific other molecules ◦ Oxygen, Nitrogen, Fluorine  This is a very strong bond, but not as strong as a covalent bond.

11.  Held together by covalent bonds  Also has hydrogen bonds between water molecules

12. Hydrogen Bonding Allows For… Cohesion: water molecules stick together Adhesion: water molecules stick to other charged substances Surface Tension: water molecules resist an external force