Bellwork. Write the electron configurations for magnesium and chlorine. How many electrons do these elements have in their highest energy level?. Valence electrons are the electrons in the highest occupied energy level of an atom.
The number of valence electrons largely determines the chemical properties of an element.
Lewis Dot Diagrams
A Lewis dot diagram illustrates valence electrons as dots (or other small symbols) around the chemical symbol of an element.
Lewis Dot Structures for Atoms
See supercool handout
Classwork- Draw dot structures for the following elements and write which energy level the valence electrons are found in.
1. Hydrogen 2. Helium 3. Sodium 4. Magnesium 5. Aluminum 6. Silicon 7. Phosphorous 8. Oxygen 9. Flourine 10. Sulfur 11. Chlorine 12. Krypton 13. Iodine 14. Arsenic 15. Calcium 16. Tin 17. Xenon
To draw a Lewis Dot Structure for an ion
1. Draw the structure for the neutral atom.
Example for Cl-
2. Add or subtract electrons depending on the ions charge. add an electron for each negative charge
subtract an electron for each positive charge
3. Place your structure in [brackets] and label the charge.
Draw dot structures for the following ions
18. H- 19. H+ 20. Na+ 21. Be2+
22. Al3+ 23. Li+ 24. Ca2+ 25. O2-
26. F- 10. S2- 27. Cl- 28. I-
30. Why don’t noble gases form ions?