1. ELECTRONS!!! Parts of an atom

2. Electrons Negative charge Located outside the nucleus in an electron cloud They are organized into shells Move very quickly – impossible to see where they are Scientists figured out where they ‘hang out’ Help create bonds between elements

3. Valence electrons are located in the outer shell or energy level. Helium 4.00260 He 2 2 Total Number of electrons = 2 Valence Electrons = 2

4. Valence electrons are located in the outer shell or energy level. Lithium 6.941 Li 3 2- 1 Total Number of electrons = 3 Valence Electrons = 1

5. Sodium 22.98977 Na 11 2- 8 -1 4 & 5. Atomic mass is the number of proton and neutrons 1. Electron configuration2. 2+8+1 = 11 total electrons 3. Valence electrons 6. 23 7 & 8. Atomic number = the number of protons P: 11 N: 12

6. The Bohr Model – Aluminum (Al) 1. Determine the # of protons, neutrons, and electrons. P = 13 N = 14 e- = 13 (electron configuration: 2-8-3)

7. The Bohr Model – Aluminum (Al) Draw a circle for the nucleus – fill in the number of protons and neutrons P+ 13 N 14

8. The Bohr Model – Aluminum (Al) Draw first energy level, draw in a maximum of 2 electrons. P+ 13 N 14

9. The Bohr Model – Aluminum (Al) Draw second energy level, draw in a maximum of 8 electrons. P+ 13 N 14

10. The Bohr Model – Aluminum (Al) Draw third energy level, draw in a maximum of 8 electrons. P+ 13 N 14

11. Let’s Try One Together… Please draw the Bohr Model of Nitrogen (N)… Please draw the Bohr Model of Sodium (Na)…

12. The Lewis Structure Determine the amount of valence electrons using the periodic table’s electron configuration. 2-8-3 Draw a symbol for Aluminum and place the outer most energy level of electrons around it … Al

13. Let’s Try One Together… Please draw the Lewis Structure of Nitrogen (N)… Please draw the Lewis Structure of Sodium (Na)…