2. Periodic Table  Organized like a big grid  Has rows (left to right horizontally) called periods  Has columns (top to bottom vertically) called groups  Each element (made up of specific atoms) is placed in a specific location based on its atomic structure

3. Periodic Table  Elements in the same row (period) or column (group) share certain similarities/characteristics  All elements in a period (row) have the same number of electron shells  All elements in a group (column) have the same number of electrons in their outer electron shells

4.  Periodic Table Song Periodic Table Song

5. Understanding Elements  Atomic Number  Located in the top center of the element box  Is the number of protons in the nucleus of the element  Also is the number of electrons orbiting the nucleus of the element

6. Understanding Elements  Chemical Symbols  A code for the chemical element  Usually comes from the modern name of the element  Some get their symbol from the name in Latin

7. Understanding Elements  Mass Number  Located in the bottom center of the element box  The number of protons plus neutrons

8. Practice- Nitrogen  Protons=  Electrons=  Neutrons=

9. Practice- Chlorine  Protons=  Electrons=  Neutrons=