1. The Periodic Table & Electron Energy Levels

2. Energy Levels
Electrons surround the nucleus of an atom in regions called energy levels.

3. Periods on the Periodic Table
Each period has a new electron energy level
Period 1 = 1 energy level
Period 2 = 2 energy levels
Period 3 = 3 energy levels

4. Atom models
When drawing an atom, the nucleus (made of protons and neutrons) is in the center.
Each energy level (filled with electrons) is a new circle around the nucleus.
How many electrons are in this atom?
Can you name the element?
6 electrons, means it has 6 protons
It is Carbon (atomic number 6)

5. Valence electrons - the number of electrons in the outermost shell
How many valence electrons are in Si? 4
How many valence electrons are in Ge? 4 Si Ge

6. Each group has the same number of. electrons in the outermost energy
Each group has the same number of electrons in the outermost energy level. (valence electrons)

7. Valence electrons of elements on the periodic table

8. Summary of the Table’s arrangement
Elements are arranged by increasing atomic number
Elements in the same period have the same number of electron energy levels
Elements in the same group the same number of valence electrons
Valence electrons are the electrons found in the outermost energy level.

9. Can you predict the electron arrangement just by looking at the element’s position on the table?