3. Valence Electrons The electrons in the outermost energy level (farthest away from the nucleus). Very important because they determine how an element will react or combine with other substances

4. Valence electrons vs. electrons 1 valence electron 1 electron total in atom 7 valence electrons 9 electrons total in atom 2 valence electrons 12 electrons total in atom

5. Valence Electrons Full outer shell = nonreactive (stable) –Will not bond/combine with others IT’S HAPPY, HAPPY, HAPPY 1 5 6 7 8 4 3 2

6. Valence Electrons NOT full outer shell = reactive (unstable) –Will react/combine with others to create compounds –NOT happy, happy, happy –ALL ATOMS WANT TO BE STABLE! So they combine with others

7. Stable or Unstable? Unstable/not full REACTIVE Unstable/not full REACTIVE stable/ full UNREACTIVE stable/ full UNREACTIVE

8. Reactivity 1-2 Valence Electrons = High Reactivity Only needs to get rid of 1-2 6-7 Valence Electrons = High Reactivity Only needs to get 1-2 3-5 Valence Electrons = Low Reactivity

9. Practice Go back to the Bohr models that you drew and 1. Identify and Label the number of valence electrons 2. Explain whether it would be reactive or unreactive & WHY.

10. Summary Statement Using the Bohr models you drew and your SPM, write a paragraph showing you have hit the learning targets for Protons and Valence Electrons