1. Compounds & Molecules Review: What is an atom? Smallest unit of matter that has the same defined properties Name the 3 subatomic particles that make up an atom. Protons, Neutrons, Electrons List the 6 most common elements (atoms) in living things. Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur

2. Compounds & Molecules Review: What is an atom? Smallest unit of matter that has the same defined properties Name the 3 subatomic particles that make up an atom. Protons, Neutrons, Electrons List the 6 most common elements (atoms) in living things. Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur

3. Compound  Two or more atoms joined together by chemical bonds.  The properties of the compound are different than properties of the individual atoms.  Examples:  Water (H 2 O)  Carbon dioxide (CO 2 )  Salt (NaCl)

4. Valence Electrons  Chemical bond: attraction that holds two atoms together. The attraction involves electrons.  Valence electrons are located in the outer shell of an atom.  When these valence electrons are gained, lost, or shared this forms a bond, and therefore a compound.

5. Chemical Bond  Valence electrons determine if atoms will form a bond  Two types of bonds  Ionic Bond  Covalent Bond

6. Ionic Bond  Electrons are transferred from one atom to another.  Ion: an atom that has gained or lost one or more electron(s). - +

7. Ionic Bond  Ionic bonds are WEAK!

8. Covalent Bond  Atoms share a pair of electrons and form each bond.  Bonds are STRONG!!  Carbon forms covalent bonds. We’ll be focusing on these types of bonds this year!

9. Covalent Bond  Atoms share a pair of electrons and form each bond.  Bonds are STRONG!!  Carbon forms covalent bonds. We’ll be focusing on these types of bonds this year! Now they are sharing 2 pairs of electrons. This forms 2 covalent bonds

10. Covalent Bond  Atoms share a pair of electrons and form each bond.  Bonds are STRONG!!  Carbon forms covalent bonds. We’ll be focusing on these types of bonds this year! Now they are sharing 2 pairs of electrons. This forms 2 covalent bonds

11. Two Types of Compounds Ionic bonds Covalent bonds Ionic Compound Molecule ex: NaCl ex: H 2 O, C 6 H 12 O 6, CO 2