1. Elements!

2. Elements ► A pure element is made of many of the same atoms. ► Common elements- Aluminum, Oxygen, Carbon (about 100 others) ► Elements cannot normally be broken apart into smaller substances Demitri Mendeleev- Russian chemist who developed the first periodic table in 1869. http://www.germes-online.com/direct/dbimage/50327532/Aluminum_Alloy_Pipe.jpg http://www.jinshanmines.com/i/photos/Jinshan_GoldBar.jpg The periodic table organizes elements by common characteristics! http://serc.carleton.edu/images/usingdata/nasaimages/peri odic-table.gif

3. Atomic Model and Subatomic Particles Atomic Model has changed dramatically through history Subatomic particles make up all atoms Subatomic particles

4. Protons Found in the nucleus (center of atom) Found in the nucleus (center of atom) The electric charge is positive (+) The electric charge is positive (+) Weighs 1 amu Weighs 1 amu (atomic mass unit) (atomic mass unit) Each element has a unique number of protons (All Oxygen atoms have 8 protons; all Iron have 26) Each element has a unique number of protons (All Oxygen atoms have 8 protons; all Iron have 26) Atoms are identified by their number of protons.

5. Neutrons Also makes up part of nucleus Also makes up part of nucleus No electric charge No electric charge Weighs 1 amu Weighs 1 amu Number of neutrons in the nucleus can change (Isotopes) Number of neutrons in the nucleus can change (Isotopes)

6. Electrons Found surrounding the nucleus in energy levels Found surrounding the nucleus in energy levels Negatively (–) charged particle Negatively (–) charged particle Weighs 1/2000 amu Weighs 1/2000 amu At one time thought to be nuclear garbage. Now, the most important part of chemistry At one time thought to be nuclear garbage. Now, the most important part of chemistry VIP of Chemistry VIP of Chemistry

7. Electron Energy Levels Electrons have energy (they have motion) Electrons surround nucleus in energy levels Electrons fill the lowest energy level first which is closest to the nucleus