1. Oxidation Number

2. Why do Ions form? In order to understand why ions form, you need to know how Electrons are arranged! Where are electrons located???

3. Quick Review of Electron Configuration Electrons are found in the electron cloud, but they’re not just placed anywhere. Electrons are found on different energy levels around the nucleus, and each energy level has a maximum number of electrons that it can hold 1 st level = 22 nd level = 8 3 rd level = 184 th level = 32 Keep in mind, these are the maximum they can hold and not always the most stable configuration.

4. How do they get in there? Electrons start at the lowest level and work their way up, so always start in the first level. How many does the first level hold? They fill in a the first level before going on to the next. NOTE: if it is the outermost energy level, 8 is maximum number of electrons

5. Take the element Boron! How many Protons? How many Neutrons? How many Electrons? Where will they go? 5 6

6. Take the element Neon! How many Protons? How many Neutrons? How many Electrons? Where will they go? 10

7. Put on your thinking caps What do you remember about the Noble gases? Stable because of its unique electron formation, stable outer energy level! Octet Rule – Every atom wants to be in a stable form, this occurs when an atom has a stable outer energy level. (Usually 8 valence electrons in it outer energy level – A few exceptions….)

8. Unlocking the secrets of bonding, one electron at a time So, Atoms want to always be stable, but how can we determine what they will do? It’s all based on their number of valence electrons (electrons in outermost energy level). Lets go back to Boron!

9. Look at Boron in it’s normal state  Not stable! – NO OCTET! so what is easier and quicker for this atom? Gain 5 more or loose 3? And the winner is….. STABLE 1st ENERGY LEVEL

10. Oxidation Number Congrats! You just determined the oxidation number for Boron! Oxidation number is the number of electrons an atom gains or loses when bonding. Ox-a- what?!

11. All the steps you need 1) Find the element and figure out how many electrons it normally would have. (Remember it’s the same as Protons) 2) Ask yourself, how many valence electrons does this atom have? (Those are the ones on the outer energy level) 3) Would it be quicker to add and get 8 valence electrons, or lose them and go down to a stable lower level? (I don’t think you need a hint here, it’s literally that easy)

12. Practice A)NitrogenB) Fluorine C) PhosphorusD) Chlorine

13. What did you notice? What did you see about atoms that are in the same groups? Remember that these elements in the same columns have similar electron configurations!!!! SO…..Every atom in the same group has the same electron configuration! Ready for a big helping hint??? Get out your Periodic Table and check this out!